Question

Find the area of the regular trapezoid. The figure is not drawn to scale. The top side is 4, the bottom side is 7, and both side sides are 5.

Answer 1

A regular trapezoid is shown in the picture attached.

We know that:
DC = minor base = 4
AB = major base = 7
AD = BC = lateral sides or legs = 5

Since the two legs have the same length, the trapezoid is isosceles and we can calculate AH by the formula:

AH = (AB - DC) ÷ 2
      = (7 - 5) ÷ 2
      = 2 ÷ 2
      = 1

Now, we can apply the Pythagorean theorem in order to calculate DH:
DH = √(AD² - AH²) 
      = √(5² - 1²)
      = √(25 - 1)
      = √24
      = 2√6

Last, we have all the information needed in order to calculate the area by the formula:

$A = \frac{(AB + CD)DH}{2}$

A = (7 + 5) × 2√6 ÷ 2
   = 12√6

The area of the regular trapezoid is 12√6 square units.