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One of the legs of a right triangle is twice as long as the other, and the perimeter of the triangle is 35. Find the

lengths of all three sides, to two decimal places.

i would appreciate if you showed work so i know how you did it!

1 Answer

5 votes

Answer:

6.68, 13.37, 14.95

Explanation:

One of the legs is twice as long as the other.

b = 2a

The perimeter is 35.

35 = a + b + c

The triangle is a right triangle.

c² = a² + b²

Three equations, three variables. Start by plugging the first equation into the second and solving for c.

35 = a + 2a + c

c = 35 − 3a

Now plug this and the first equation into the Pythagorean theorem:

(35 − 3a)² = a² + (2a)²

1225 − 210a + 9a² = a² + 4a²

1225 − 210a + 4a² = 0

Solve with quadratic formula:

a = [ -(-210) ± √((-210)² − 4(4)(1225)) ] / 2(4)

a = (210 ± √24500) / 8

a ≈ 6.68 or 45.82

Since the perimeter is 35, a = 6.68. Therefore, the other sides are:

b ≈ 13.37

c ≈ 14.95

User Janley Zhang
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