Anybody Know This. ?

4 feet

Step-by-step explanation:

In order to determine the length of side, we need to use what is called the Pythagorean theorem, which states: a² + b² = c² The a and b in this equation are both of the sides of the triangle that we call legs. (I have attached a picture for reference if you do not know what sides I am referring to). The c in this equation refers to the hypotenuse of the triangle. (Again, please refer to the attached photo).

So now, we need to plug in the information we already know into this equation. The height of the ramp will be our a and the distance from the box will be our b. We can see that the hypotenuse (c) is labeled as 5, so we can fill in that information in our equation.

a²+b²=5² (simplify by squaring the 5)

a²+b²=25

Next, we know that the height of the box is 3 feet, which let's us know that our a is 3. Let's plug this new information in.

3²+b²=25 (simplify by squaring the 3)

9+b²=25 (simplify by substracting the 9 from both sides)

b²=16

Hey! Now our equation looks much simpler! Now, all we need to do it square root both of the sides in order to get b by its self.

b²=16

√b² = b

√16 = 4

Final b = 4

I truly hoped this explanation helped! If you feel you still need a bit of help, David May explains the Pythagorean theorem very well in his video titled, "Find The Hypotenuse Using Pythagorean Theorem | Dave May Teaches" if you would like to check it out. Take care! :)