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Help this is so confusing 20 points for answers

Help this is so confusing 20 points for answers-example-1
User Vbandrade
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1 Answer

6 votes

Answer:

(18π +4) cm ≈ 60.55 cm

Explanation:

You want the perimeter of a figure bounded by two semicircles and a straight line segment.

Perimeter

The perimeter of the figure is the sum of the lengths of the curves and lines that form its boundary. Here, one boundary is a semicircle of diameter 16 cm, another boundary is a semicircle of diameter 20 cm, and a straight line forms the remaining boundary.

Semicircles

The length of a semicircle is half the circumference of a full circle of the same diameter:

boundary length = 1/2(πd)

The smaller semicircle has a length of ...

boundary length (small) = 1/2π(16 cm) = 8π cm

The larger semicircle has a length of ...

boundary length [large] = 1/2π(20 cm) = 10π cm

Line segment

The length of the line segment is the difference of the diameters:

line segment length = (20 cm) -(16 cm) = 4 cm

Sum

The perimeter is the sum of these lengths:

P = boundary length (small) + boundary length (large) + line segment length

P = (8π +10π +4) cm = 18π +4 cm ≈ 60.55 cm

The perimeter of the figure is about 60.55 cm.

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Additional comment

The perimeter is closer to 60.549 cm, so rounds to 60.5 cm.

User Bhaskar
by
8.2k points

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