Answer:
A = 222 units^2
Explanation:
To find the area of this trapezoid, first draw an imaginary horizontal line parallel to AD and connecting C with AB (Call this point E). Below this line we have the triangle CEB with hypotenuse 13 units and vertical side (21 - 16) units, or 5 units. Then the width of the entire figure shown can be obtainied using the Pythagorean Theorem:
(5 units)^2 + CE^2 = (13 units)^2, or 25 + CE^2 = 169. Solving this for CE, we get |CE| = 12.
The area of this trapezoid is
A = (average vertical length)(width), which here is:
(21 + 16) units
A = --------------------- * (12 units), which simplifies to:
2
A = (37/2 units)(12 units) = A = 37*6 units = A = 222 units^2