Use 10% to find 40% of 130:
number
13
130
0% 10%
percent
40%
100%

52

Step-by-step explanation:

I don't really know what the other numbers are for but I'll just answer the first line.

Basically, you have to find what 10% of 130 is and multiply that number by 4.

130/10 = 13 (10% of 130)

4(13) = 52 (40% of 130)

You can verify this by typing in your calculator (130 x 0.40) and you should get 52.

You can also take 100% of 130 and substract by 60% of 130 to find 40%.

i'm sorry i don't know

step-by-step explanation:

the answer is b.

64

step-by-step explanation:

c=2πr=2·π·8≈64