Question

If △DEF is an obtuse angled triangle, and ∠E = 120⁰ , ∠D = 40⁰ then ∠F =​

Answer 1

Answer:

we know that

the sum of all angle in triangle is 180

therefore '. 120+ 40 + f= 180

160 +f = 180

F = 180 -160

F = 20

this answer help you

Answer 2

Step-by-step explanation:

This ΔABC is an isosceles triangle. In this kind of triangle, two of the sides are equal.

So if AB=AC,

Then vertex= angle A and

Base angles= angle B and angle C which are equal.

Let the base angles angle B and angle C be x.

Since the sum of the angles of a triangle=180°,

Therefore,

angle A + angle B + angle C = 180°

= 120° + x+x= 180°

= 120° + 2x= 180°

= 2x = 180°-120°

= 2x = 60°

= x = 60°/2 =30°

Therefore,

Angle A= 120°

Angle B= 30°

Angle C= 30°.