Answer:
Explanation:
Remark
The method of finding the area of the ring is to find the area of the outer ring and subtract the area of the hole in the middle.
Outer ring
r = 10 + 4 = 14 inches
Area = pi * r^2
Outer ring area = pi * 14^2
Outer ring area = 196 pi
Inner hole
Area unshaded part = pi * r^2
r = 10
Area = pi * 10^2
Area = 100 pi
Area of the shaded part
area of the shaded part = outter circle area - inner circle area
outter circle area = 196 * pi
inner circle area = 100 pi
Area of the shaded part = 196 pi - 100 pi
Area of the shaded part = 96 pi
pi = 3.14
Area of the shaded part = 96 * 3.14
Answer area of the shaded part = 301.44
Answer area of the shaded part = 301.4 rounded to the nearest tenth
The second problem is done exactly the same way. Only the numbers have been changed. I will give you the answers to the main part of the problem and you can try and get what I got. If we disagree, be preparred to tell me what you got so I correct mine if it is wrong.
Outter Radius = 18 + 8 = 26
Area of outter circle = pi * 26^2
Area of outter circle = 676 pi
Inner Circle area hole = pi * 18^2
Inner Circle area hole = 324 pi
Area of the shaded part = outter circle - inner circle
Area of the shaded part = 676 pi - 324 pi
Area of the shaded part = 352 pi
pi = 3.14
Area of the shaded part = 352 * 3.14
Answer: area of shaded part rounded to 1 decimal place = 1105.3