8
round each number to the nearest 10, then
640 ÷ 80 = 8 ← estimate
Answer:
- Exact Area = 210.25pi - 210
- Approximate Area = 450.185
The units for the area are in square inches or in^2. The approximate value shown above is when using pi = 3.14
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Explanation:
Use the pythagorean theorem to find the length of the hypotenuse
a^2 + b^2 = c^2
20^2 + 21^2 = c^2
400 + 441 = c^2
c^2 = 841
c = sqrt(841)
c = 29
The hypotenuse is 29 inches long. This is the diameter of the circle. Half of that is the radius at r = d/2 = 29/2 = 14.5 inches.
The area of the circle is...
A = pi*r^2
A = pi*(14.5)^2
A = pi*210.25
A = 210.25pi
Which is exact in terms of pi
We'll subtract off the triangular region as this isn't shaded in. The area of the triangle is base*height/2 = 20*21/2 = 420/2 = 210 square inches.
So the shaded region is therefore 210.25pi - 210 square inches
This approximates to 210.25*3.14 - 210 = 450.185 when using the approximation pi = 3.14; use more decimal digits of pi to get a more accurate value.
Answer:
42
Step-by-step explanation:
hey 42+9=51 so this can be the ✔️answer
