Question

This is a polygon. I can’t find the missing angle ?

Answer 1

This is a lot of calculation.

So we know that the sum of angles for any heptagon is 900, because heptagon can be divided into five non-overlapping triangles and sum of angles of each triangle is 180.

Now you just add up all angles and simplify the equation:

900 = (6x - 8) + 120 + (7x - 64) + (5x - 4) + 135 + (3x + 31) + (4x + 15)

900 = 25x + 225

Now it's just regular algebra equation. You can solve for x:

675 = 25x

x = 27

So the value of x is 27