Question

ABCD is a parallelogram. If A = (x +20) and D = (x -20° then find
the measures of B and C.​

Answer 1

Answer:

This is the correct answer

Answer 2

✪ Question ✪

ABCD is a parallelogram. If ∠A = (x + 20)° and ∠D = (x - 20)° then find the measures of ∠B and ∠C.

✪ Given ✪

• ∠A = (x +20)°
• ∠D = (x -20)°

✪ To find ✪

The measures of ∠B and ∠C.

✪ Solution ✪

As in the figure in the attachment, ∠A and ∠D are adjacent angles.

We know that the sum of the adjacent angles of a parallelogram is 180°.

∴ ∠A + ∠D = 180

⇒(x + 20) + (x - 20) = 180

⇒x + 20 + x - 20 = 180

⇒2x = 180

⇒x = 180/2

⇒x = 90

✪ Hence ✪

x = 90

∠A = (x + 20)° = (90 + 20)° = 110°

∠D = (x - 20)° = (90 - 20)° = 70°

As the opposite angles of a parallelogram are equal,

∠A = ∠C = 110°

∠D = ∠B = 70°

✪ Therefore ✪

The measure of ∠B and ∠C are 70° and 110° respectively.

๑ Hope this helps you. ๑