Based on the right-angled triangles shown above, the values of x are;
1. x = 15.9
2. x = 17.5
3. x = 7.3
4. x = 12
In Mathematics and Geometry, Pythagorean's theorem is an Euclidean postulate that can be modeled or represented by the following mathematical equation:

Where:
- a is the opposite side of a right-angled triangle.
- b is the adjacent side of a right-angled triangle.
- c is the hypotenuse of a right-angled triangle.
Part 1.
By applying Pythagorean's theorem, the right-angled triangle can be modeled by this equation;

x = 15.9
Part 2.
By applying Pythagorean's theorem, the right-angled triangle can be modeled by this equation;

x = 17.5
Part 3.
By applying Pythagorean's theorem, the right-angled triangle can be modeled by this equation;

x = 7.3
Part 4.
Since triangle DEF is an equilateral triangle, it is composed of a 30-60-90 right-angled trangle;
x = hypotenuse/2
x = 24/2
x = 12