Eric Nicholas K's answer to LockB's Secondary 3 A Maths Singapore question.
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Two kinds of triangles you must know
First is a pair of geometrically similar triangles. Ratio of areas will be the square of the length scale.
Second is a pair of triangles whose perpendicular heights are the same but whose bases are different. Ratio of areas will be the length scale itself since the other dimension (height) is irrelevant for triangles with the same height.
First is a pair of geometrically similar triangles. Ratio of areas will be the square of the length scale.
Second is a pair of triangles whose perpendicular heights are the same but whose bases are different. Ratio of areas will be the length scale itself since the other dimension (height) is irrelevant for triangles with the same height.
Date Posted:
3 years ago
ratio of areas for triangles with the same height but different base length is only the length ratio itself because 1/2 and height can be cancelled out from the fraction when comparing?
Yes, because both “1/2” are the same and both perpendicular heights are the same. Just like common numbers in the numerator and denominator cancel out (like 4x / 4 = x).
If the values of the areas are not given and they ask you to find ratios of areas, you can assign an area as “1 unit”. You will see these very frequently in Sec 4.
ok thx :)
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