Question

In the isosceles triangle pqr angle p and angle Q are equal angle pqr is an exterior angle of triangle pqr the measures of angle prq and angle PRS are (2 x - 30)° and (6 X + 10)° respectively find the measure of angle prq and angle PRS also find the measure of angle p and angle q
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Answer 1

Answer:

Using the theorem that if the side of a triangle is produced then the interior angle is equal to the sum of two interior opposite angles of the triangle.

Let ΔABC be a triangle where the side BC is produced.

By the theorem we have

∠A+∠B=100

o

…………..(1)

It is given that the interior opposite angles are equal i.e., ∠A=∠B.

∴ Equation (1) becomes

2∠A=100

o

⇒∠A=50

o

⇒∠B=50

o

Using angle sum property of a triangle,

Sum of all angles of a triangle =180

o

⇒∠A+∠B+∠C=180

o

⇒100+∠C=180

o

[from (1)]

⇒∠C=180

o

−100

o

⇒∠C=80

o

.

Hence ∠A=50

o

∠B=50

o

∠C=80

o

.