Question

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The sum of the angles of a triangle is 180. the first and second angles are equal. The third angle is 2.5 times the first. How large is the first angle?

Answer 1

Answer: 40°

Explanation:

First angle can be represented as x, second angle can be represented as y, and the third angle can be represented as z.

x + y + z = 180°

Since the first and second angles are equal, x = y, we can replace y with x.

x + x + z = 180°

The third angle is 2.5 times the first, which can be written as 2.5x.

x + x + 2.5x = 180 (now we solve for x)

4.5x = 180

x = 40°

Check:

40 + 40 + 40(2.5) = 180°

180°=180°