Question

the base angles of a isosceles triangle is 20 more than thrice the vertex angle. find the value of equal angles.


need step by step solution.

Answer 1

Answer:

40 is the answer nice thanks cool and vote

Answer 2

Answer:

The equal angles of the triangle are 80.

Step-by-step explanation:

Given,

The base angle of an isosceles triangle is 20 more than thrice the vertex angle.

To find,

The value of the equal angles

Recall the formula

The base angles of an isosceles triangle are equal.

The sum of the three angles of a triangle is 180 degrees.

Solution:

Let 'x' be the base angle of an isosceles triangle and 'y' be the vertex angle.

Then the three angles of the isosceles triangle are x,x,y.

Since the sum of three angles of a triangle is 180degrees,

we have x+x+y  = 180

2x + y = 180 -------------------(1)

Since the base angle of an isosceles triangle is 20 more than thrice the vertex angle, we have

x = 20+3y ---------------------(2)

Substitute the value of 'x' in (1) we get

2( 20+3y) + y = 180

40+6y+y=180

7y=180 - 40 = 140

y = 20

The vertex angle = 20

From (2) we have

x = 20+3y

= 20 + 60

= 80

The base angle of the triangle = 80

∴ The equal angles of the triangle are 80.

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