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What is the perimeter of an isosceles right triangle with a leg equal to 3?

(Round your answer to the nearest tenth.)

User Andrey
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1 Answer

13 votes
13 votes

Answer:

10.2

Explanation:

You want the perimeter of an isosceles right triangle with a leg length of 3.

Isosceles right triangle

An isosceles right triangle with a leg length of 1 has a hypotenuse (c) given by ...

c² = a² +b² . . . . . . where 'a' and 'b' are the leg lengths

c² = 1² + 1² = 2

c = √2

That is, the ratios of the lengths of the sides in an isosceles right triangle is ...

1 : 1 : √2

Perimeter

The sum of the lengths of these sides is ...

1 + 1 + √2 ≈ 3.4142

The given triangle is scaled up from this by a factor of 3, so its perimeter is ...

P = 3×3.4142 ≈ 10.2 . . . . units

The perimeter of the triangle is about 10.2 units.

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Additional comment

It is worthwhile to remember the relationship between side lengths for this "special" right triangle. You will see it again.

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What is the perimeter of an isosceles right triangle with a leg equal to 3? (Round-example-1
User Bettyanne
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2.8k points