Question

Special Right Triangles
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Answer 1

fourth option

Explanation:

Since the sides are congruent, then the diagonal divides the square into 2 right isosceles triangles.

Thus the 2 base angles are congruent with measure 45°

Hence y = 45

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Using the cosine ratio in the right triangle and the exact value

cos45° =
`(√(2) )/(2)` , then

cos45° =
`(adjacent)/(hypotenuse)` =
`(x)/(10)` =
`(√(2) )/(2)` ( cross- multiply )

2x = 10
`√(2)` ( divide both sides by 2 )

x = 5
`√(2)`

Answer 2

d

Explanation: