Isosceles and Equilateral Triangle Theorems

Find the value of x. (Hint: What type of triangle is this?)

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Find the value of y.

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Find the value of x. (Hint: what kind of triangle is this?)

Find the value of y.

Find the value of x.

Find the value of x. (Hint: what kind of triangle is this?)

Find the value of y.

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Find the value of z.

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Triangle DEF is isosceles, angle D is the vertex angle, DE = x + 7, DF = 3x – 1, and EF = 2x + 5. Find the value of x. (Hint: draw a picture)

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Triangle LMN is isosceles, angle L is the vertex angle, LM = 3x – 2, LN = 2x + 1, and MN = 5x – 2.

Find the value of x.

(Hint: draw a picture)

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