Answer:
AC = 40
Step-by-step explanation:
A quadrilateral is a polygon shape with four sides and four angles. The interior angle of a quadrilateral sums up to 360°.
A parallelogram is a quadrilateral (has four sides and four angles) in which has two pair of opposite sides are parallel to each other. The diagonals of a parallelogram bisect each other.
Given parallelogram ABCD:
Diagonals AC and BD bisect each other at point E. Hence:
AC = AE + CE (line segment addition postulate)
Also:
AE = CE (diagonal BD bisects AC at point E).
Hence; x + 16 = 5x
5x - x = 16
4x = 16
x = 4
AE = x + 16 = 4 + 16 = 20; CE= 5x = 5(4) = 20
AC = AE + CE = 20+ 20 = 40
