Answer:
12 feet
Explanation:
i always forget abt this thing but its important to remember the pythagorean theorm is a thing. the whole a^2 + b^2 = c^2 thing. at first i looked back at sohcahtoa but thats for an angle lol. sooooooo, knowing that the hypotenuse is the ladder and the ground is the base and seeing that we need to find a since b is the base and c is the hypotenuse, we should rearrange the equation so that we can find a so now it should look like this: c^2 - b^2 = a^2. then we plug in our numbers to get this: 15^2 - 9^2 = a^2. next we would square the 15 and 9 so now our equation looks like this: 225 - 81 = a^2. now we subtract so we have: 144 = a^2. then we should find the square root of each. the square root of a^2 is a and the square root of 144 is 12 so now we have the answer: a = 12. i hope that makes sense.
i hope this helps :))