Answers

2016-04-08T10:55:39+05:30
This question can be solved by exterior angle property also.
hope it will satisfy you
0
can you solve mine other questions too please
where is the question i will try
ok
in maths
The Brainliest Answer!
2016-04-08T10:59:28+05:30
Let the triangle be ΔABC and m∠A = 70 and m∠B = m∠C = a.

Let D be a point on ray BC such that ∠ACD is exterior angle of ΔABC at point C.
Thus, according to question, m∠ACD = b.

Now, for ΔABC,
m∠A + m∠B + m∠C = 180
∴ 70 + a + a = 180
∴ 70 + 2a = 180
∴ 2a = 180 - 70
∴ 2a = 110
a = 55

We know that measure of an exterior angle is the sum of measures of its interior opposite angles. 

In this case ∠ACD is exterior angle  and its interior opposite angles are ∠CAB and ∠ABC.

∴ m∠ACD = m∠CAB + m∠ABC
∴ b = 70 + a
∴ b = 70 + 55
∴ b = 125

Thus, a = 55° and b = 125°
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