Question

In the figure, the base of the triangle is extended on both sides. Which of
these CANNOT be said with certainty?
a
a) a + b + c = 180 degrees
c) c+e=180 degrees
b) b + d = 180 degrees
d) d + e - 180 degrees​

Answer 1

Answer:

we extend BC on both ends, then the angles would be,

∠ACD=180−C

∠ABF=180−B

Sum of the 2 exterior angles=∠ACD+∠ABF

=(180−C)+(180−B)

=360−(B+C)

=360−(180−A)=180+A

∠A is always positive.

∴ sum of the angles is greater than 180°.

Answer 2

Answer:

∠A is always positive.

∴ sum of the angles is greater than 180°.