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(6 + 2)(4)
a = ½(8)(4)
a = ½(32) = \( \frac{32}{2} \)
a = 16

A rectangle is a parallelogram containing four right angles. Opposite sides (a = c, b = d) are equal and the perimeter is the sum of the lengths of all sides (a + b + c + d) or, comonly, 2 x length x width. The area of a rectangle is length x width. A square is a rectangle with four equal length sides. The perimeter of a square is 4 x length of one side (4s) and the area is the length of one side squared (s²).

The area of a triangle is equal to ½ base x height:

a = ½bh
a = ½ x 4 x 7 = \( \frac{28}{2} \) = 14

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.

The first step to solve a quadratic expression that's not set to zero is to solve the equation so that it is set to zero:

y² + y - 2 = -y + 1
y² + y - 2 - 1 = -y
y² + y + y - 3 = 0
y² + 2y - 3 = 0

Next, factor the quadratic equation:

y² + 2y - 3 = 0
(y - 1)(y + 3) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (y - 1) or (y + 3) must equal zero:

If (y - 1) = 0, y must equal 1
If (y + 3) = 0, y must equal -3

So the solution is that y = 1 or -3