GO PYTHAGORAS
for a right triangle with legs legnth a and b with hyptonuse c,
the legnths of the sides relate as follows
a^2+b^2=c^2
where the wall meets the ground is the right angle
legs are 15 and 8
hypotnuse=c=legnth of ladder
15^2+8^2=c^2
225+64=c^2
289=c^2
sqrt both sides
17=c
the legnth of the ladder is 17ft
