In a quadrilateral ABCD, ∠A=90∘,∠B=3x,∠C=3x+5,∠D=8x−15. Then the value of ∠D is
Since the sum of interior angles of a quadrilateral is 360∘ 90+3x+3x+5+8x−15=36090+14x−10=36014x=360−80=280⇒x=20∠D=8x−15=8(20)−15=145∘
The following figure shows a quadrilateral in which sides AB and DC are parallel. If ∠A:∠D=4:5, ∠B=(3x−15)o and ∠C=(4x+20)o, find each angle of the quadrilateral ABCD.
In parallelogram ABCD, if ∠A = 2x + 15o, ∠B = 3x - 25o, then value of x is: