Flashcards · Maths
Geometry and Measures
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What do angles on a straight line add up to?
\(180^\circ\).
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What do angles around a point add up to?
\(360^\circ\).
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What are vertically opposite angles?
The equal angles opposite each other where two straight lines cross.
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What do the angles in a triangle add up to?
\(180^\circ\).
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What do the angles in a quadrilateral add up to?
\(360^\circ\).
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What is the rule for the exterior angle of a triangle?
It equals the sum of the two opposite interior angles.
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Which angles are equal and form a Z shape between parallel lines?
Alternate angles.
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Which angles are equal and form an F shape between parallel lines?
Corresponding angles.
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Which angles add up to \(180^\circ\) and form a C shape between parallel lines?
Co-interior angles.
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What is the sum of the interior angles of an \(n\)-sided polygon?
\((n - 2) \times 180^\circ\).
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What do the exterior angles of any polygon add up to?
\(360^\circ\).
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What is each exterior angle of a regular polygon with \(n\) sides?
\(360 \div n\).
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How do you find an interior angle of a regular polygon from the exterior angle?
Subtract the exterior angle from \(180^\circ\).
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What is the interior angle of a regular hexagon?
\(120^\circ\).
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A regular polygon has exterior angle \(24^\circ\). How many sides?
\(360 \div 24 = 15\).
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Why must you state the angle fact in an exam?
Mark schemes award marks for the reason as well as the answer.
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What is the formula for the area of a rectangle?
\(A = l \times w\).
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What is the formula for the area of a triangle?
\(A = \dfrac{1}{2} \times b \times h\).
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What is the formula for the area of a parallelogram?
\(A = b \times h\), using the perpendicular height.
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What is the formula for the area of a trapezium?
\(A = \dfrac{1}{2}(a + b)h\).
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How do you find the area of a compound shape?
Split it into simple shapes and add, or subtract a missing piece from a larger shape.
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What is the circumference formula?
\(C = \pi d = 2\pi r\).
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What is the formula for the area of a circle?
\(A = \pi r^2\).
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What is the relationship between diameter and radius?
The diameter is twice the radius.
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What is the area of a circle with radius 5 cm, in terms of \(\pi\)?
\(25\pi\) cm\(^2\).
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What is the circumference of a circle with diameter 14 cm?
\(14\pi\) cm.
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What is an arc?
A part of the circumference of a circle.
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What is a chord?
A straight line joining two points on a circle.
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What is a tangent?
A line that touches a circle at exactly one point.
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What is the area of a semicircle?
\(\dfrac{1}{2}\pi r^2\).
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How do you find the area of a sector (Higher tier)?
\(\dfrac{\theta}{360} \times \pi r^2\).
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What is the perimeter of a sector (Higher tier)?
The arc length plus two radii.
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What is the volume of a cuboid?
\(l \times w \times h\).
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What is the surface area of a cuboid?
\(2lw + 2lh + 2wh\).
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What is the volume of a prism?
The area of the cross-section multiplied by the length.
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What shape is the curved surface of a cylinder when it is opened out?
A rectangle.
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What is the volume of a cylinder?
\(\pi r^2 h\).
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What is the curved surface area of a cylinder?
\(2\pi r h\).
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What is the total surface area of a closed cylinder?
\(2\pi r h + 2\pi r^2\).
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What is the volume of a cylinder with radius 3 cm and height 10 cm?
\(90\pi\) cm\(^3\).
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How many millilitres are in 1 cm\(^3\)?
1 ml.
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What is the volume of a cone (Higher tier)?
\(\dfrac{1}{3}\pi r^2 h\).
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What is the curved surface area of a cone (Higher tier)?
\(\pi r l\), where \(l\) is the slant height.
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What is the volume of a sphere (Higher tier)?
\(\dfrac{4}{3}\pi r^3\).
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What is the surface area of a sphere (Higher tier)?
\(4\pi r^2\).
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What is the volume of a pyramid (Higher tier)?
\(\dfrac{1}{3} \times\) base area \(\times\) vertical height.
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What is a net?
A flat shape that folds up to make a 3D shape.
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How do you find the mass from the density and volume?
Mass \(=\) density \(\times\) volume.
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What is Pythagoras' theorem?
\(a^2 + b^2 = c^2\), where \(c\) is the hypotenuse.
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What is the hypotenuse?
The longest side of a right-angled triangle, opposite the right angle.
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How do you find the hypotenuse?
Square the two shorter sides, add them, then take the square root.
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How do you find a shorter side?
Square the hypotenuse, subtract the square of the other side, then take the square root.
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What is a Pythagorean triple?
Three whole numbers that satisfy \(a^2 + b^2 = c^2\).
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Name four Pythagorean triples.
\(3, 4, 5\), \(5, 12, 13\), \(8, 15, 17\) and \(7, 24, 25\).
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What is the hypotenuse for shorter sides 6 cm and 8 cm?
10 cm.
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What is the hypotenuse for shorter sides 9 cm and 12 cm?
15 cm.
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How can you test if a triangle is right-angled?
Check whether \(a^2 + b^2 = c^2\) for the longest side \(c\).
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How do you find the height of an isosceles triangle?
Split it down the middle and use Pythagoras with half the base.
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What is the height of an isosceles triangle with base 10 cm and sides 13 cm?
12 cm.
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Which triangle do you use to find the diagonal of a rectangle?
The right-angled triangle made by the length, the width and the diagonal.
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What is the size of a shorter side if the hypotenuse is 13 and the other side is 5?
12.
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What is \(\sqrt{20}\) in simplest surd form (Higher tier)?
\(2\sqrt{5}\).
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How do you find the distance between two points on a grid (Higher tier)?
Use the horizontal and vertical differences as the two shorter sides of a right-angled triangle.
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How do you find the diagonal of a cuboid (Higher tier)?
Use Pythagoras twice.
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What is the hypotenuse?
The longest side of a right-angled triangle, opposite the right angle.
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What is the opposite side?
The side across from the angle you are using.
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What is the adjacent side?
The side next to the angle you are using, apart from the hypotenuse.
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What is the formula for sine?
\(\sin\theta = \dfrac{O}{H}\).
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What is the formula for cosine?
\(\cos\theta = \dfrac{A}{H}\).
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What is the formula for tangent?
\(\tan\theta = \dfrac{O}{A}\).
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What does SOH CAH TOA stand for?
Sine is Opposite over Hypotenuse, Cosine is Adjacent over Hypotenuse, Tangent is Opposite over Adjacent.
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What is \(\sin 30^\circ\)?
\(\dfrac{1}{2}\).
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What is \(\cos 60^\circ\)?
\(\dfrac{1}{2}\).
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What is \(\tan 45^\circ\)?
1.
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What is \(\sin 45^\circ\) and \(\cos 45^\circ\)?
Both \(\dfrac{\sqrt{2}}{2}\).
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What are \(\sin 60^\circ\) and \(\cos 30^\circ\)?
Both \(\dfrac{\sqrt{3}}{2}\).
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What is \(\tan 60^\circ\)?
\(\sqrt{3}\).
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What is \(\sin 0^\circ\), \(\sin 90^\circ\) and \(\cos 90^\circ\)?
0, 1 and 0.
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How do you find an angle when you know two sides?
Use the inverse function, such as \(\tan^{-1}\left(\dfrac{O}{A}\right)\).
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What is the side opposite a \(30^\circ\) angle in terms of the hypotenuse?
Half of the hypotenuse.