Question

In an isosceles triangle, the base angles are equal. The vertex angle is 40°. What are the base angles of the triangle? (Remember, the sum of three angles of a triangle is 180°)​

Answer 1

Answer:

(sum of all sides of triangle =180)

only two sides of isosceles triangle are equal.

so angle A+B+C=180

angleA=40

angleB=X

angle C=X

so180-40=140

140/2=70

angle a=40

angle b =70

angle c=70

Answer 2

Answer:

Given:

• In an isosceles triangle the base angle are equal. The vertex angle is 14°.

Find:

• What are the base angle of the triangle.

Using Angle sum property:

☆ ${\sf{\underline{\boxed{\red{\sf{ Sum \: of \: all \: three \: triangles = 180°}}}}}}$

Calculations:

• Let x be the base angles and the common variable to this question.

⇒ $\sf{x + x + 14 = 180}$

⇒ $\sf{2x + 14 = 180}$

⇒ $\sf{2x = 180 - 14}$

⇒ $\sf{2x = 166}$

⇒ $\sf{x= 166 ÷ 2}$

⇒ ${\sf{\underline{\boxed{\red{\sf{x = 83° }}}}}}$