Question

Draw Equilateral triangle and mesure their angle and verify sum of all three interior angle is 180 degree

Answer 1

Answer:

Step-by-step explanation:

We know that if 2 sides of a triangle are equal, the opposite angles are equal , now, if we apply this to equilateral triangle, there are 3 pairs of equal sides , so it means all angles are equal.Now let the measure of each angle be x , then :

By angle sum property;

x + x + x = 180°

3x = 180°

x= 60°

Hence proved…..

Answer 2

Answer:

The sum of all angles are triangle is 180°.

Given :- A PQR with angles 41, 2 and 23

Prove :- 21+ 22 + 43 = 180°

Construction:- Draw a line XY passing through P parallel to QR

Proof:

For lines XY & QR,

with transversal PQ

22 = L4

(Alternate angles)

For lines XY & QR,

with transversal PR

23 = L5

(Alternate .(2) angles)

Also, for line XY

21+ 24 + 25 = 180°

21 + 2 + 3 3 180°

(Linear pair)

(From (1) and (2))

Hence, sum of all angle of a triangles are equal.

Hence proved

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