Scientific notation is the way that scientists easily handle very large numbers or very small numbers. For example, instead of writing 0.0000000056, we write 5.6 x 10-9.
So, if we are dealing with 965000000000000, then the answer would be:
9.65 x 10^14
Since it is 25% all you would have to do is mutiply it by 4 to get 160. So in conclusion 160 is the answer.
If you're trying to find the missing side of the "triangle" (the distance from the house to where the ladder touches the ground), you would use the pythagorean theorem, a²+b²=c². (c is always hypotenuse)
a²+b²=c²
12²+b²=15²
144+b²=225
b²=81
√b²=√81
b=9
5 is the difference.
Note: Minuend - Subtrahend = Difference