1) The sum of an Octagon is 1080°
And all it's sides are congruent (same size, same angle measure)
And an Octagon has 8 sides
So do,
1080 ÷ 8 = 135°
Each side equals to 135°
2) A triangle adds up to 180°.
We have one angle that's 45° and another angle that has a little □ in it.
That little square (□) is called a right angle which = 90°
So do
90 + 45 = 135
180 - 135 = 45
So the value of x is 45°