Inner angles

The magnitude of the internal angle at the central 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=2180γ=218072=54  β=α=54=54   A=α=54=54
C+B = 180° C=180B=18054=126
A+D = 180    D=C=126=126

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Tips for related online calculators
Calculation of an isosceles triangle.
See also our trigonometric triangle calculator.

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