The formula for area of a trapezoid is:

Sides a is the top line and side b is the base, or bottom line. Add the sides together and divide by 2. After you do that, multiply the answer by the height.
Height is the length between the two sides, a and b.
Answer:

Step-by-step explanation:
Answer:
w = -20
Step-by-step explanation:
8-3=5
-w/4=5
5*4=20
-w=20
-1/20=-20
w=-20
Answer:
800 people a year
Step-by-step explanation: