Answer:
Look below.
Step-by-step explanation:
Good ol' Pythagorean Theorem.
To find the short side of the larger triangle, we'll use this equation:
![a^{2} +b^{2} =c^{2} \\\\9^2+b^2=10^2\\81+b^2=100\\](https://tex.z-dn.net/?f=a%5E%7B2%7D%20%2Bb%5E%7B2%7D%20%3Dc%5E%7B2%7D%20%5C%5C%5C%5C9%5E2%2Bb%5E2%3D10%5E2%5C%5C81%2Bb%5E2%3D100%5C%5C)
You can solve the rest on your own.
Use the same type of equation for the smaller triangle, except your b would be the hypotenuse, so that equation would look something like this:
![3^2+x^{2} = b^2](https://tex.z-dn.net/?f=3%5E2%2Bx%5E%7B2%7D%20%3D%20b%5E2)
Hope it helped! Also, there seems to be a help video, if you didn't understand this explanation, why don't you go ahead and watch it?