Enlarged by scale of 5 means multiplies by 5:
4 x 5 and 3.5 x 5
So Area:
= 1/2 ( 4 x 5)( 3.5 x 5)
= 1/2 (4 x 3.5) x 5^2
so answer is the last one
She should have multiplied 1/2(4)(3.5) by 5^2
Area of a triangle is 1/2 base * height * the scale factor squared
A = 1/2b*h*sf^2
A = 1/2 * 4 * 3.5*5^2
Choice D
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