Question

If angles a and b are supplementary angles and angle a is 85°, what would be the size of angle b?

Answer 1

∠b = 95°

Explanation:

We're given that angles ∠a and ∠b are supplementary.

We know that supplementary angles add up to 180°.

Since ∠a and ∠b are supplementary, the following is true:

`\bf{a+b=180}`

We know that ∠a = 85:

`\bf{85+b=180}`

Subtract 85 from each side:

`\bf{b=180-85}`

`\bf{b=95^o}`

Therefore, ∠b = 95°.

Answer 2

b = 95°

Explanation:

supplementary angles sum to 180° , then

a + b = 180° , that is

85° + b = 180° ( subtract 85° from both sides )

b = 95°