Answer:
<h3>137</h3>
Step-by-step explanation:
Answer: 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
Answer: The value of x must be 13
Step-by-step explanation:
1. draw the parallelogram with side 20cm and 25cm respectively and also the diagonal as well.
2.Clearly it forms a triangle in the parallelogram with three known lengths of side.
3.Using the cosine rule : c^2=b^2+c^2 -2bc cos c to find the obtuse angle.
