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7. The length of a minute hand of a clock is 3.5cm. Find the angle it turns through if it

sweeps an area of 48 cm. (Taken=22/7)
(3 marks)
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User Martinez
by
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1 Answer

4 votes

Answer:

The angle it turns through if it sweeps an area of 48 cm² is 448.8°

Explanation:

If the length of a minute hand of a clock is 3.5cm, to find the angle it turns through if it sweeps an area of 48 cm, we will follow the steps below;

area of a sector = Ф/360 × πr²

where Ф is the angle, r is the radius π is a constant

from the question given, the length of the minute hand is 3.5 cm, this implies that radius r = 3.5

Ф =? area of the sector= 48 cm² π =
(22)/(7)

we can now go ahead to substitute the values into the formula and solve Ф

area of a sector = Ф/360 × πr²

48 = Ф/360 ×
(22)/(7) × (3.5)²

48 = Ф/360 ×
(22)/(7) ×12.25

48 = 269.5Ф / 2520

multiply both-side of the equation by 2520

48×2520 = 269.5Ф

120960 = 269.5Ф

divide both-side of the equation by 269.5

448.8≈Ф

Ф = 448.8°

The angle it turns through if it sweeps an area of 48 cm² is 448.8°

User Ichbinallen
by
4.5k points