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secondary 3 | A Maths
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secondary 3 chevron_right A Maths chevron_right Singapore

need help with this qn, pls explain too :)

Date Posted: 3 years ago
Views: 153
Eric Nicholas K
Eric Nicholas K
3 years ago
Oh, this kind. Wait.

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Eric Nicholas K
Eric Nicholas K's answer
5997 answers (Tutor Details)
1st
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.
LockB
LockB
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?
Eric Nicholas K
Eric Nicholas K
3 years ago
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).
Eric Nicholas K
Eric Nicholas K
3 years ago
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.
LockB
LockB
3 years ago
ok thx :)