Figure abcd is a parallelogram. if abcd is also a rhombus, what must be the value of x? 13 15 18 23

First option 13

Solution

If ABCD is a rhombus, the diagonals must be perpendicular, then the angle (5x+25)° must be a right angle (90°):

(5x+25)°=90°

5x+25=90

Solving for x: Subtracting 25 both sides of the equation:

5x+25-25=90-25

Subtracting:

5x=65

Dividing both sides of the equation by 5:

5x/5=65/5

Dividing:

x=13

The value of x must be 13