Magnitude 23271

In an isosceles triangle, the angle at the primary vertex is 20 ° smaller than twice the magnitude of the angle at the base. What are the interior angles of a triangle?

Correct answer:

A =  80
B =  50
C =  50

Step-by-step explanation:


A=2·B - 20
A+B+C=180
B=C

A-2B = -20
A+B+C = 180
B-C = 0

Row 2 - Row 1 → Row 2
A-2B = -20
3B+C = 200
B-C = 0

Row 3 - 1/3 · Row 2 → Row 3
A-2B = -20
3B+C = 200
-1.333C = -66.667


C = -66.66666667/-1.33333333 = 50
B = 200-C/3 = 200-50/3 = 50
A = -20+2B = -20+2 · 50 = 80

A = 80
B = 50
C = 50

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Calculation of an isosceles triangle.
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