You need to use the Pythagorean Theorem, which is $\displaystyle a^{2}+b^{^{2}} = c^{^{2}}$.

Add the first two values and you get $\displaystyle 2$. Take the square root of both sides and you get $\displaystyle \sqrt{2}$.

$\displaystyle \text{Hypotenuse}=\sqrt{\text{(leg 1)}^2+\text{(leg 2)}^2}$

Using the numbers given to us by the question,

$\displaystyle \text{Hypotenuse}=\sqrt{2^2+5^2}=\sqrt{29}=5.38$ units

Use the Pythagorean Theorem to find the length of the hypotenuse.

$\displaystyle (\text{Hypotenuse})^2=(\text{leg 1})^2+(\text{leg 2})^2$

$\displaystyle \text{Hypotenuse}=\sqrt{4^2+5^2}=\sqrt{41}\:cm$

Use the Pythagorean Theorem to find the hypotenuse.

$\displaystyle 16^2+20^2=\text{Hypotenuse}^2$

$\displaystyle 656=\text{Hypotenuse}^2$

$\displaystyle \sqrt{656}=25.61=\text{Hypotenuse}$

To solve this problem, we must utilize the Pythagorean Theorom, which states that:

$\displaystyle a^{2}+b^{2}=c^{2}$

We know that the base is $\displaystyle 7$, so we can substitute $\displaystyle 7$ in for $\displaystyle a$.  We also know that the height is $\displaystyle 4$, so we can substitute $\displaystyle 4$ in for $\displaystyle b$.

$\displaystyle 7^{2}+4^{2}=c^{2}$

Next we evaluate the exponents:

$\displaystyle 7^{2}=49$

$\displaystyle 4^{2}=16$

Now we add them together:

$\displaystyle 49+16=65$

Then, $\displaystyle 65=c^{2}$.

$\displaystyle 65$ is not a perfect square, so we simply write the square root as  $\displaystyle \sqrt{65}$.

$\displaystyle c=\sqrt{65}$

To solve this problem, we are going to use the Pythagorean Theorom, which states that $\displaystyle a^{2}+b^{2}=c^{2}$.

We know that this particular right triangle has a base of $\displaystyle 3$, which can be substituted for $\displaystyle a$, and a height of $\displaystyle 9$, which can be substituted for $\displaystyle b$. If we rewrite the theorom using these numbers, we get:

$\displaystyle 3^{2}+9^{2}=c^{2}$

Next, we evaluate the expoenents:

$\displaystyle 3^{2}=9$

$\displaystyle 9^{2}=81$

$\displaystyle 9+81=c^{2}$

$\displaystyle 9+81=90$

Then, $\displaystyle 90=c^{2}$.

To solve for $\displaystyle c$, we must find the square root of $\displaystyle 90$. Since this is not a perfect square, our answer is simply $\displaystyle c=\sqrt{90}$.

According to the Pythagorean Theorem, the equation for the hypotenuse of a right triangle is $\displaystyle a^{2} + b^{2}=c^{2}$. Plugging in the sides, we get $\displaystyle 5^{2}+8^{2}=c^{2}$. Solving for $\displaystyle c$, we find that the hypotenuse is $\displaystyle \sqrt{89}$:

$\displaystyle 25+64=c^2$

$\displaystyle 89=c^2$

By the Pythagorean Theorem, the square of the hypotenuse is equal to the sum of the squares of the other two sides.

Let $\displaystyle c=$ hypotenuse and $\displaystyle s=$ side length.

$\displaystyle c^2=s^2+s^2\Rightarrow c^2=(2t)^2+(2t)^2\Rightarrow c^2=8t^2\Rightarrow c=\sqrt{8t^2}=2\sqrt{2}t$

The pythagorean theory should be used to solve this problem. 

$\displaystyle a^{2}+b^{2}+=c^{2}$

$\displaystyle 7^{2}+12^{2}+=c^{2}$

$\displaystyle 49+144=c^{2}$

$\displaystyle 193=c^{2}$

$\displaystyle \sqrt{193}=c$