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The length of the base of an isosceles triangle is x. The length of a leg is 5x−5. The perimeter of the triangle is 122. Find x.

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Final answer:

The perimeter of the isosceles triangle is composed of the base and two equal legs. With the given perimeter of 122, the base being x, and the legs as 5x-5, we solved the equation 122 = x + (5x-5) + (5x-5) to find that x is 12.45.

Step-by-step explanation:

The perimeter P of an isosceles triangle is the sum of the lengths of its three sides.

Given that the base length is x, and the length of each of the equal legs is 5x-5, we can write the perimeter equation as:

P = x + (5x-5) + (5x-5)

Since the perimeter P is given to be 122:

122 = x + (5x-5) + (5x-5)

122 = x + 10x - 10 - 5

Now, simplifying the equation:

122 = 11x - 15

Adding 15 to both sides:

137 = 11x

Dividing both sides by 11:

x = 12.45 (rounded to two decimal places)

So, the value of x is 12.45.

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