Answer:
9
Step-by-step explanation:
54+81=9(6+9)
9 times 9 equals 81
3.4+0.4+4.17=7.97 you just have to try different combinations of different numbers with the decimals.
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
