The large right triangle and the smaller right triangle on the left are similar triangles. For a better understanding, see image attached.
Make a comparison.
The proportion of corresponding sides in similar triangles are the same.
[tex] \cfrac{\text{hypotenuse}}{\text{horizontal}} = \cfrac{\text{hypotenuse}}{\text{horizontal}}[/tex]
Input the numbers
[tex] \cfrac{x}{9}= \cfrac{25}{x} [/tex]
Do cross multiplication
x² = 25 × 9
x² = 225
x = √225
x = 15
The value of x is 15
