Question

If in triangle ABC angle A-B=420, B-C=210, B=?​

Answer 1

Answer:

180⁰- 42⁰+21⁰=117⁰ is equal to angle b

Answer 2

Answer

It is given that ∠A+∠B=108∘…(1)

We know that the sum of all the angles in a triangle is 180∘.

So we can write it as

∠A+∠B+∠C=180∘

By substituting ∠A+∠B=108∘ in the above equation

108∘+∠C=180∘

On further calculation

∠C=180∘−108∘

By subtraction

∠C=72∘

It is given that ∠B+∠C=130∘

By substituting the value of ∠C

∠B+72∘=130∘

On further calculation

∠B=130∘−72∘

By subtraction

B=58∘

By substituting ∠B=58∘ in equation (1)

So we get

∠A+∠B=108∘

∠A+58∘=108∘

On further calculation

∠A=108∘−58∘

By subtraction

∠A=50∘

Therefore, ∠A=50∘,∠B=58, ∠C=72