Help with mathematics

Answer:
155 ft squared
Step-by-step explanation:
base = 15 ft * height = 20ft
b*h = 310
divide this by 2
310/2 = 155 SQUARED
Answer:
3,750
Step-by-step explanation:
First Step: Multiply
20×15×25=7,500
Second Step: Divide
7,500/2=3,750
Explaining How to Do It.
The triangle is actually half of a rectangle in the picture multiplying all of this then dividing it makes the half of the rectangle.