To fond the area of a trapezoid, add the top and bottom together, divide that by 2, than multiply by the height.
Area = (8+12)/2 = 20/2 = 10
10 x 9 = 90 square centimeters.
Answer:
boys = 250
girls = 150
Step-by-step explanation:
5g = 3b eq. 1
g + b = 400 eq. 2
g = girls
b = boys
From the eq. 2
g = 400 - b
Replacing this last eq. on eq. 1:
5(400-b) = 3b
5*400 + 5*-b = 3b
2000 - 5b = 3b
2000 = 3b + 5b
2000 = 8b
2000/8 = b
250 = b
From eq. 2
g + 250 = 400
g = 400 - 250
g = 150
Check:
from eq. 1
5*150 = 3*250 = 750
5 units left and 7 units up
