Inner angles

The magnitude of the internal angle at the main vertex C of the isosceles triangle ABC is 72°. The line p, parallel to the base of this triangle, divides the triangle into a trapezoid and a smaller triangle. How big are the inner angles of the trapezoid?

Correct answer:

A =  54 °
B =  54 °
C =  126 °
D =  126 °

Step-by-step explanation:

γ=72 ° α=β α+β+γ=180° α+α+γ=180°  α=180γ2=180722=54 ° β=α=54 °  A=α=54=54°
B=β=54=54°
C+B=180° C=180B=18054=126°
A+D=180 °  D=C=126=126°



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