Answer:
plug in the numbers for radius, and know your formulas. a diameter is 2 times a radius so
Pi or 3.14 times D is the same as 2 times pi times radius.
a) 8 x 10^3 or 8000
b) 8 x 10^-2 or .08
Explanation: Refer to a guide on rounding sig figs
20+x+45+90= <u>x + 155</u>
