The formula for circumference is circle diameter x π:

c = πd
c = 8π

The area of a trapezoid is one-half the sum of the lengths of the parallel sides multiplied by the height:

a = ½(b + d)(h)
a = ½(8 + 8)(4)
a = ½(16)(4)
a = ½(64) = \( \frac{64}{2} \)
a = 32

The first step to solve a quadratic equation that's set to zero is to factor the quadratic equation:

y² - 9y + 14 = 0
(y - 2)(y - 7) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (y - 2) or (y - 7) must equal zero:

If (y - 2) = 0, y must equal 2
If (y - 7) = 0, y must equal 7

So the solution is that y = 2 or 7

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.

4a⁸ - 2a⁸ = 2a⁸

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.