Answer:
Follow the Pythagoreas theorm. You typically need to find
, which is the hypotonuse, but because we already know this, we can rearrange the equation to make sense.
Personally, I like to substitute with non-related numbers, such as 1 and 2. In the following example, the sides are 1 unit, 2 units, and 5 units. First, I like to figure out the sum of
and
.
EX:
![1^2+2^2= 5](https://img.qammunity.org/2021/formulas/mathematics/high-school/3gjh3wkj6orh0g6fmwt0eyoow95o1q6f37.png)
![25^2=5](https://img.qammunity.org/2021/formulas/mathematics/high-school/7hkrsdcvspk6k8hc6pjrzlmvxmoo7qad2j.png)
I can rearrange this so that one leg and the hypotenuse are on the same side:
![25^2-1^2=2^2](https://img.qammunity.org/2021/formulas/mathematics/high-school/f3cj3w57urkc6732n0q5k51bffzceko76i.png)
Now I can take out the example numbers, and substiture in the variables.
![c^2-a^2=b^2](https://img.qammunity.org/2021/formulas/mathematics/high-school/ecnzwnx4xc47h9garuq9is5nus0ct04iy9.png)
Now all I have to do is fill in the known variables!
![15^2-12^2=b^2](https://img.qammunity.org/2021/formulas/mathematics/high-school/7uqu88td16flkcpjry7w39bdva96n0vqis.png)
Solve!
![225-144=80](https://img.qammunity.org/2021/formulas/mathematics/high-school/wcfeq9tzxxkt644l8f2gaxizsh5qtn1l8l.png)
We're not done- we have to find the square root of 81!
It's 9m!
Finally, we can check our work by plugging
and
into the normal equation. It checks out!
![12^(2) +9^(2) = 15^(2) \\=225 =225\\225=225](https://img.qammunity.org/2021/formulas/mathematics/high-school/e4wu6an6yibpir8r3v71liuw9uu5jvsioy.png)
Have questions? Let me know!