Answer:
Your missing a number and your answer is 12
Step-by-step explanation:
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
8 quarters = (8 x .25) = $2.00
5 dimes = (5 x .10) = $.50
$2.00 + $.50 = $2.50
8 + 5 = 13
It’s called an equilateral triangle because all sides are even. A triangle equals 180 degrees. So, 60 degrees x 3 sides = 180 degrees