Answer:
There are two possibilities: 1) A is the hypotenuse: [tex]C \approx 18.74[/tex], 2) A is not the hypotenuse: [tex]C \approx 21.19[/tex]
Step-by-step explanation:
Let be C the remaining side of the triangle. Given that triangle is right-angled and the remaining side can be found by Pythagorean Theorem, there are two options by using the two known sides:
1) A is the hypotenuse
[tex]20^{2} = 7^{2} + C^{2}[/tex]
[tex]C^{2} = 20^{2}-7^{2}[/tex]
[tex]C = \sqrt{20^{2}-7^{2}}[/tex]
[tex]C \approx 18.74[/tex]
2) A is not the hypotenuse
[tex]C^{2} = 20^{2} + 7^{2}[/tex]
[tex]C = \sqrt{20^{2}+7^{2}}[/tex]
[tex]C \approx 21.19[/tex]