Answer:
1) 4.2 inches
2) 63 inches²
Explanation:
If the base is 15 inches, we can assume that the opposite side is also 15 inches. 15 + 15 = 30. If we subtract 30 from the total perimeter, we will have the sum of the last two sides.
38.4 - 30 = 8.4
Now that we have the sum we can now find the exact length with division:
8.4/2 = 4.2 inches
To find the area, we multiply these together.
4.2 * 15 = 63