In a parallelogram, opposite angles are the same.
Because you are given angle C is 70 degrees, angle R is also 70 degrees.
An exterior angle of a triangle is equal to the sum of the two opposite inside angles.
Angle KSO is an exterior angle to the triangle made from ORS,
So angle KSO would equal the sum of angle O and angle R.
Angle KSO = 65 + 70 = 135 degrees.