The sum of all angles of a triangle is equal to 180°
On a isosceles triangle, the base angles are the same.
We add them together 56° + 56° = 112°
To know X, we subtract 112° from the total
180° - 112° = 68°
X = 68°
OR as an equation
56 + 56 + x = 180
112 + x = 180
x = 180 - 112
x = 68