Answer: x=7.21
Step-by-step explanation: This is a right triangle- remember the Pythagorean theorem: a² + b² = c². To find leg a, you'd use a = √(c² - b²) **leg a would be the side that is labeled with 12. To find leg b, you'd use b = √(c² - a²) *this is the equation we need. To find the hypotenuse, or c, you'd use c = √(a² + b²). This equation works for right triangles only.
Hope this helps :)