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Q: Find the area of an equilateral triangle has a perimeter of 21 inches round the answer to one decimal place?

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Find the area of an equilateral triangle that has a perimeter of 21 inches. Round the answer to one decimal place.

9 inches

Ok if the triangle is equilateral then all the sides have to have the same length. Since the perimeter is 45 inches that means each side is 15 inches. 45 / 3 = 15 Now if he dilates the triangle by a scale factor of 0.6 we have to multiply the length of each side by 0.6. 15 * 0.6 = 9 So the answer is 9 inches

By definition, an equilateral triangle has all three sides of equal length! So it is impossible for it to have sides of length 10 inches and 7 inches!

Solve the problem in stages:Solve for the length of the triangle side.Perimeter = sum of all the sides. As equilateral, all sides equal so 3 x side_length = 90 inside_length = 90in / 3 = 30in.Pentagon side is triangle_side + 2in, thus Pentagon_side = 30in + 2in = 32inThere are 5 sides to a pentagon, each 32in long, so its perimeter is 5 x 32in = 160in.

Related questions

Find the area of an equilateral triangle that has a perimeter of 21 inches. Round the answer to one decimal place.

21.2 sq inches.

Area of equilateral triangle: 0.5*7*7*sin(60 degrees) = 21.2 square inches

18 inches and it is an equilateral triangle

6in.

21.20

12 inches

The perimeter is the sum of all sides. An equilateral triangle has three sides of equal length. So if one side is 5 inches, and we have three of these, we get a perimeter of 15 inches.

2.5 inches

9 inches

6 inches

It is: 3*9 = 27 inches

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