An isosceles triangle has two sides of equal length. An equilateral triangle has three sides of equal length. In a right triangle, two sides meet at a right angle.

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.

7c - 1 < \( \frac{c}{-8} \)
-8 x (7c - 1) < c
(-8 x 7c) + (-8 x -1) < c
-56c + 8 < c
-56c + 8 - c < 0
-56c - c < -8
-57c < -8
c < \( \frac{-8}{-57} \)
c < \(\frac{8}{57}\)

The surface area of a cylinder is 2πr² + 2πrh:

sa = 2πr² + 2πrh
sa = 2π(9²) + 2π(9 x 6)
sa = 2π(81) + 2π(54)
sa = (2 x 81)π + (2 x 54)π
sa = 162π + 108π
sa = 270π

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.

To combine like terms, add or subtract the coefficients (the numbers that come before the variables) of terms that have the same variable raised to the same exponent.

7a + 8a = 15a