let's find the area of the outer circle and the inside circle
the inside's circle area
A= π x 6²=36π
the outer's
A' = π x 4x²= 4πx²
A'-A=4πx²- 36π=160πcm² equivalent to x²- 9=40, so x²=49 implies x =sqrt(49)=7, x=7.
Answer: AC=12 cm
Step-by-step explanation:
To solve this problem you must apply the law of sines, as you can see below:

Where:
a=13
A=85.2°
B=71.6°
Therefore, you must solve for b, then, you obtain that the lenght AC asked in the problem above is:

Answer:
1. x=5
2.x=-33/8
3.x=10
4.x=5
Step-by-step explanation:
Answer:
m + m = 36
18 + 18 = 36
Step-by-step explanation: