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The angle of a sector of a circle of radius 10.5cm is 48°, Calculate the perimeter of the sector
A. 8.8cm
B. 25.4cm
C. 25.6cm
D. 29.8cm
QUICK ANSWER…
D
DETAILS…
If the angle of a sector of a circle of radius 10.5cm is 48°, the perimeter of the sector will be = 29.7979cm
Perimeter of a sector = length of arc + 2r
Where r = radius of the circle.
Now, lets find the length of arc of the sector.
Length of arc = θ/360 × 2πr
Length of arc = 48/360 × 2 × 3.142 × 10.5
Length of arc = 8.7979cm
Therefore, perimeter of the sector = 8.7979 + 2 × 10.5
perimeter of the sector = 8.7979 + 21 = 29.7979 = 29.8cm
Now for the right answer to the above question:
- Option A is incorrect.
- Option B is not correct.
- C is incorrect.
- D is the correct answer.
KEY-POINTS…
You may please note these/this:
- Perimeter of a sector of a circle = length of arc + 2r.
- Length of arc = θ/360 × 2πr.
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/ culled from 2021 JAMB-UTME MATHEMATICS question 17 /