2384598 + 6000000 = 8384598
There is a formula for Sum of interior angles of a polygon:

This figure has 7 sides, n = 7

Add up all the given angles,
Subtract from 900,
This will give you value of x.
2/3 = 5
4/6 = 10
6/9 = 15
8/12 =20
10/15 = 25 this one
12/18 = 30
10/15
3x+4x=2
You add 3x and 4x which gets you 7x
7x=2
You divide both sides of the equation by 7
x=2/7
This will be your result