Answer:
B
Step-by-step explanation:
sorry if its wrong
Answer:
A
Step-by-step explanation:
Sn=a(n-1) d
this formula for Calculating arithmetic sequence
First set up a proportion because they are similar triangles:
9/3x-20 = (72+9)/(56+3x-20)
9/3x-20 = 81/3x+36
9(3x+36) = 81(3x-20)
27x+324 = 243x-1620
1944 = 216x
x = 9
Side a can be broken into to rectangles having areas:
(12-8)*4 and 8*12 so the area of side A is
A=16+96
A=112cm^2
