Question

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Class : IX - G2
Admission No.: 11413
Subject :HYE - Mathematics
Q. 10 In a triangle ABC, if angle A = 7x + 10°,
angle B = 2x + 5° and angle C = x + 15°, then the
value of x is​

Answer 1

as we know that

A+B+C = 180

> 7x+10+2x+5+x+15 = 180°

> 10x+30 = 180°

> 10x = 180-30 => 150

> x = 150/10 => 16°

> x = 15°

Now

>A=7×15+10° [x=15]

> A= 105+10°=>115

> A = 115°

similarly

B = 2x15+5 [ x=16°] , C= 10+15

B = 30+5 => 35° ,. C= 30°

so'. A= 115°,. B=. 35 °. C = 30°

if you want to check your answer [optional just for checking your answer]

then

A+B+C= 180

115+35+30 = 180

180=180

hence our answer is right