=( choose the correct simplification of the expression a to the 12th power times b to the 8th power all over a to the 2nd power times b to the 4th power
a10b4
a6b2
1 over a to the 10th power times b to the 4th power
1 over a to the 14th power times b to the 12th power

Okay, so the answer is a10b4. Take a look at the attachment to see how I got that answer.
The explanation: when you have a fraction where the base is the same variable (here it is a) and they have a certain exponent, you can simply subtract the exponents, just like I did here: a12/a2 = a12-2 = a10.

See explanation

Step-by-step explanation:

Your question isn't complete but I'm assuming that you want to calculate the radius.

Circumference of a circle = 2πr

where Circumference = 18.9 meters

Radius = Unknown

π = 3.14

We then put the values into the formula which will be:

C = 2πr

18.9 = 2 × 3.14 × r

18.9 = 6.28r

r = 18.9 / 6.28

r = 3

The radius = 3 meters

Assuming you probably want to get the diameter, we multiply the radius by 2. This will be:

= 2 × 3

= 6 meters