Answer:
1) 81.67 cm² (Option A)
2) 28.26 m² (Option B)
3) 153.86 mi.² (Option D)
4) 329.90 m² (Option A)
5) 63.585 ft.² (Option C)
Step-by-step explanation:
<u>GENERAL FORMULAES TO BE USED IN THIS QUESTION :-</u>
Diameter of a circle with radius 'r' = 2r
Area of a circle with radius 'r' = πr²
<u>SOLUTION :-</u>
1) Diameter of the dinner plate = 10.2 cm
Radius of the dinner plate = 10.2/2 = 5.1 cm
⇒ Area of the circle = π(5.1)² = 26.01π cm² ≈ 81.67 cm²
2) Length of his leash = 3m
⇒ Area the dog has to run around = π(3)² = 9π m² = 28.26 m²
3) Radius of the circular range of storm = 7 mi.
⇒ Area of the circular range of storm = π(7)² = 49π mi.² = 153.86 mi.²
4) Diameter of carousel = 20.5 m
Radius of carousel = 20.5/2 = 10.25 m
⇒ Area of the carousel = π(10.25)² = 105.0625π m² ≈ 329.90 m²
5) Radius of the range of sprinkler = 4.5 ft.
⇒ Area of the range of sprinkler = π(4.5)² = 20.25π ft.² = 63.585 ft.²
