Special Right Triangles
Need help don’t understand this.

fourth option

Step-by-step 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° = , then

cos45° = = = ( cross- multiply )

2x = 10 ( divide both sides by 2 )

x = 5

sas (side angle side)

aa(angle angle)

sss(side side side)

sas you have to find two sides with an angle in between

aa you find two angles because it will always add up to 180

sss find all sides

step-by-step explanation: