Answer:
x ≈ 8.9
Explanation:
You want the value of x in the diagram showing two right triangles.
Pythagorean theorem
The Pythagorean theorem tells you the relationship between legs 'a' and 'b' and hypotenuse 'c' in a right triangle is ...
a² +b² = c²
Smaller triangle
For the smaller triangle, this tells you the square of the length of its hypotenuse is ...
c² = 2² +4² = 4 +16 = 20
Larger triangle
That square can be used directly in the equation for the larger triangle:
20 +x² = 10²
x² = 100 -20 = 80
x = √80 ≈ 8.9
The value of x is about 8.9 units.