Verified Answer :

A = ¹/₂bh
A = ¹/₂(15)(15)
A = ¹/₂(225)
A = 112.5in²

iGreen

Since it's equilateral, all sides should also be 15 inches.

A = 1/2 b h

A = 1/2 15 15

Multiply:

A = 112.5