The cards Question When are two variables in direct proportion? Tap to flip Answer When they have a constant multiplicative relationship. Question Give one context in which direct proportion can be used. Tap to flip Answer e.g. converting a compound measure or converting currency. Question Two quantities are in direct proportion. If one of them is zero, what must the other be? Tap to flip Answer Zero as well. Question Which straight-line graphs show direct proportion? Tap to flip Answer Only straight-line graphs that pass through the origin (0, 0). Question When are two shapes similar? Tap to flip Answer When the only difference between them is their size; their side lengths are in the same proportions. Question When is a property of a shape invariant? Tap to flip Answer When that property has not changed after the shape is transformed. Question What is an enlargement? Tap to flip Answer A transformation that causes a change of size. Question What is a scale factor? Tap to flip Answer The multiplier between similar shapes that describes how large one shape is compared to the other. Question After an enlargement, how are the object and the image related? Tap to flip Answer They are similar. Question In an enlargement, what happens to every length of the object? Tap to flip Answer Each length is multiplied by the scale factor. Question What happens to the perimeter of a shape when it is enlarged? Tap to flip Answer The perimeter is multiplied by the scale factor. Question Which law shows that enlarging a shape multiplies its perimeter by the scale factor? Tap to flip Answer The distributive law. Question Do scale factors have dimensions or depend on the unit of measurement? Tap to flip Answer No. Scale factors have no dimensions and are not linked to specific units. Question A length of 23 cm corresponds to a length of 69 cm on a similar shape. What is the scale factor? Tap to flip Answer 3 (it stays 3 if the same lengths are measured in inches: 9 in and 27 in). Question When are two shapes congruent? Tap to flip Answer When one can fit exactly on top of the other using rotation, reflection or translation. Question For the SSS congruence criterion, what do you need to know about a triangle and its image? Tap to flip Answer All three side lengths of each. Question If two triangles are congruent, how do their corresponding angles compare? Tap to flip Answer The angle pairs are the same. Question Is knowing all three angles enough to prove two triangles are congruent? Tap to flip Answer No. Two equilateral triangles have the same angles but are not guaranteed to be congruent; they are similar. Question For the SAS congruence criterion, what do you need to know? Tap to flip Answer Two side lengths and the angle between them, in both the triangle and its image. Question Why do two sides and an angle that is not between them (SSA) not guarantee congruence? Tap to flip Answer Two different triangles can be constructed from that information. Question For the ASA congruence criterion, what do you need to know? Tap to flip Answer Two angles and the length between them, in both the triangle and its image. Question From which congruence criterion is the ASA rule derived? Tap to flip Answer SAS. Question For the RHS congruence criterion for right-angled triangles, which lengths do you need? Tap to flip Answer The hypotenuse and one other side length. Question What does Pythagoras' theorem state? Tap to flip Answer In a right-angled triangle, the sum of the squares of the two shorter sides equals the square of the hypotenuse. Question Can you assume an angle in a diagram is a right angle because two line segments look perpendicular? Tap to flip Answer No. Question What is one advantage of scaling the perimeter of a shape? Tap to flip Answer It can reduce the number of calculations. Question A scale is written 1 : 400 with no units given. What units do the two parts have? Tap to flip Answer The same unit for both parts, e.g. 1 cm : 400 cm. Where this deck sits in the curriculum Curriculum National Curriculum for England Stage GCSE (Years 10–11) Course GCSE Maths Unit Similarity Tiers foundation and higher England's National Curriculum sets what is taught; the units and their order are Oak National Academy's. Flash Feed is not affiliated with Oak or any exam board.
How this deck was checked On 2026-11-02, every card was compared with its source: the lessons of Oak National Academy, a public body funded by England's Department for Education that publishes lessons for the national curriculum. Because the cards come from those lessons, no second source was sought. The comparison was done automatically, not by a teacher, so a card can still be wrong. Flash Feed is not affiliated with any source named here.
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A Maths lesson by Oak National Academy licensed under Open Government Licence (OGL)
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