ΔOLD and ΔNEW are similar triangles. The area of
ΔNEWis 875 square units. Determine the area of
ΔOLD.

_____________square units

Question

ΔOLD and ΔNEW are similar triangles. The area of
ΔNEWis 875 square units. Determine the area of
ΔOLD.

_____________square units

anonymous · Answer

attachment

directrix · Answer

@Pash007 

If two triangles are similar, the square of the scale factor of the two triangles is equal to the ratio of the areas of the triangles.

directrix · Answer

Scale Factor: 12/20 = 3/5

(3/5)²  = OLD/875

27/125  = OLD/875

Cross multiply and solve for OLD.

anonymous · Answer

125OLD=23625
OLD= 189

anonymous · Answer

Thats the answer that I got, but it was incorrect

anonymous · Answer

@Directrix

directrix · Answer

(3/5)² = OLD/875

9/25 = OLD/875

Cross multiply and solve for OLD.

OLD = 315

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@Pash007  I apologize for my computational error.

Click on the attachment to see the source of my mistake.