Question

one angle, A, of parallelogram ABCD is (x + 10)° , its opposite angle measure (3x - 2)° . what is the measure of B?

Answer 1

Since opposite angle are equal in ||gm.

(x + 10)° = (3x - 2)°

2x = 12

x = 6

Measure of A = 16°

Measure of B = 180° - 16° = 164°

Answer 2

Since opposite angles in parallelogram are equal

So,

$(x + 10) \degree = (3x - 2) \degree \\ x - 3x = - 2 - 10 \\ - 2x = - 12 \huge \: \downarrow \\ \bf \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: Cancelling \: ( - ) \: sign \\ 2x = 12 \\ x = \frac{12}{2} = 6$