Answer:
The final balance is $23,232.33.
The total compound interest is $3,232.33.
Two lines are perpendicular if and only if the product of their slopes is - 1.
So, you just need to find the slope of each line and find out the product of their slopes.
I will do one example for you.
L1: y = 3x + 5
L2: y = - 3x + 14
L3: y = -x/3 + 14
The slope of a line is the coefficient of the x.
So the slopes are:
L1: slope 3
L2: slope -3
L3: slope -1/3
So now multiply the slopes of each pair of lines:
L1 and L2: 3 * (-3) = - 9 => No, they are not perpendicular
L2 and L3: (-3) * (-1/3) = 1 => No, they are not perpendicular
L1 and L3: (3) * (-1/3) = -1 => Yes, they are penpendicular.
3 feet 8 inches converted to inches is 3x12+8=44inches
44inches times 4 pieces is 176 inches.
176 inches converted back to feet and inches is 176/12=14 feet 8 inches so he would need 15 feet of board
There are 31+42+50+61=184 total females, and 50+61=111 females in grades 11 and 12, so the percentage is 111/184*100=60.33 percent, which can be rounded to 60%.
We set up the equation 580/4 = 725/x. Since we know these are proportional, we can cross-multiply and solve to get x = 5.