Question

Q9 In figure if angleA + angleB + angleC+ angleD+angleE+ angleF = k right angles, then find value of k
(a) 2
(C) 4
(b) 3
(d) 5​

Answer 1

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$\small\mathbf\red{{Explaination\::-}}$

See In the above figure there are two triangles

Now we all know that the sum of triangles. is180°

So Angles ( A + B + C + D +E + F) = (2*180)°

= 360°

=4 right angles

Ans.c)4

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Answer 2

There are two triangles: ΔABC and ΔFDE

In ΔABC,

By angle sum property of triangles,

∠A+∠B+∠C = 180° --- (eqtn. 1)

In triangle In ΔFDE,

By angle sum property of triangles,

∠F+∠D+∠E =  180° --- (eqtn. 2)

Adding equation 1 and 2, we get

∠A+∠B+∠C+∠D+∠E+∠F = 360°

But, ∠A+∠B+∠C+∠D+∠E+∠F = k×90°

⇒k×90°=360°

⇒k=4

Therefore value of k is 4