Similar Triangle Area
Move Points A,B,C
Notice that c/c' = b/b' = a/a'
The ratio of the areas of two similar triangles equals the ratio of the squares of any pair of corresponding sides. Area ABC ÷ Area DEF = b^2 ÷ b'^2.
This is derived as follows: Area ABC ÷ Area DEF
= 0.5 * c * b ÷ 0.5 * c’ * b’
= c * b ÷ c’ * b’ (but c ÷ c’ = b ÷ b’)
= b * b ÷ b’ * b’ => b^2 ÷ b’^2