Answer:
125.6m^2
Step-by-step explanation:
Let R be the greater radius and r be the smaller radius
Area of the sidewalk = R^2 - r^2 - This can be the expression
= 3.14
=(R^2-r^2)
=(11^2-9^2)
=(121-81)
= 40
= 3.14 x 40
See below for the proof of the equation
<h3>How to prove the equation?</h3>
The equation is given as:

Take the LCM

Expand

Evaluate the like terms

Rewrite as:

Factorize the numerator

Divide
2(a - b)= 2(a - b)
Both sides are equal
Hence, the equation
has been proved
Read more about equations at:
brainly.com/question/2972832
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Answer:
blue = 35
green = 29
red = 38
Step-by-step explanation:
Let r = red
Let g = green
let b = blue
r + g + b = 102
r = b + 3
b = g + 6 Subtract 6 from both sides of the equation
b - 6 = g
===================
substitute for red and green
(b + 3) + b + b - 6 = 102
b + 3 + b + b - 6 = 102
Combine like terms
3b - 3 = 102
Add 3 to both sides
3b - 3 + 3 = 102 + 3
3b = 105
Divide by 3
3b/3 = 105/3
b = 35
======================
r = b + 3
r = 35 + 3
r = 38
=======================
g = b - 6
g = 35 - 6
g = 29
========================