Answer:
15 + 23 = 38
38 x 9 = 342
342 x 1/2 (basically just dividing by 2) 171
Step-by-step explanation:
Formula of a trapezoid:
B1(base 1) + B2(base 2) x H(height) x 1/2(basically just dividing by 2)
In this case,
12 and 23 are your bases, 9 is your height.
