The circumference of a circle is the distance around its perimeter and equals π (approx. 3.14159) x diameter: c = π d. The area of a circle is π x (radius)² : a = π r².

A line segment is a portion of a line with a measurable length. The midpoint of a line segment is the point exactly halfway between the endpoints. The midpoint bisects (cuts in half) the line segment.

To solve this equation, isolate the variable for which you are solving (b) on one side of the equation and put everything else on the other side.

3b - y = -3b - 4y - 1
3b = -3b - 4y - 1 + y
3b + 3b = -4y - 1 + y
6b = -3y - 1
b = \( \frac{-3y - 1}{6} \)
b = \( \frac{-3y}{6} \) + \( \frac{-1}{6} \)
b = -\(\frac{1}{2}\)y - \(\frac{1}{6}\)

An equation is two expressions separated by an equal sign. The key to solving equations is to repeatedly do the same thing to both sides of the equation until the variable is isolated on one side of the equal sign and the answer on the other.

To solve this equation, repeatedly do the same thing to both sides of the equation until the variable is isolated on one side of the < sign and the answer on the other.

b + 9 < \( \frac{b}{-4} \)
-4 x (b + 9) < b
(-4 x b) + (-4 x 9) < b
-4b - 36 < b
-4b - 36 - b < 0
-4b - b < 36
-5b < 36
b < \( \frac{36}{-5} \)
b < -7\(\frac{1}{5}\)