Question

If an angle of a parallelogram is two-third of its adjacent angle, the smallest angle of the parallelogram is

Options

• 108°

• 54°

• 72°

• 81°

Answer 1

Let one of the angle of the parallelogram as x°

Then the adjacent angle becomes `2/3 x°`

We know that the sum of adjacent angles of the parallelogram is supplementary.

Therefore,

`x + 2/3x = 180°`

    `5/3 X = 180°`

           `x = 180 (3/5)`

            x = 108°

Thus, the angle adjacent to 108°

`= 2/3 (108°)`

= 72°

Therefore, the smallest angle of the parallelogram as 72°

Hence, the correct choice is (c).