A parallelogram has sides with lengths of #12 # and #8 #. If the parallelogram's area is #12 #, what is the length of its longest diagonal? Geometry Quadrilaterals Quadrilaterals 1 Answer sankarankalyanam Apr 28, 2018 #color(green)("length of Longest diagonal " bar(AC) = 19.97# Explanation: #"Given : " AB = b = 12, AD = a = 8, Area = 12, " To find " AC = q# #bar(EC) = h = (Area) / b = 12 / 12 = 1# #bar(BE) = sqrt((BC)^2 - (CE)^2) = sqrt(a^2 - h^2)# #bar(BE) = sqrt(8^2 - 1^2) = 7.94# #bar(AE) = AB + BE = 12 + 7.94 = 19.94# #bar(AC) = sqrt((AE)^2 + (EC)^2) = sqrt(19.94^2 + 1^2) = 19.97# #color(green)("length of Longest diagonal " bar(AC) = 19.97# Answer link Related questions In a quadrilateral ABCD ,which is not a trapezium.It is known that <DAB=<ABC=60 DEGREE.moreover... A square‘s sides are tripled producing an area of 81 square feet. What is the ratio of the area... Is a rhombus always a trapezoid? In an isosceles trapezoid ABCD, AB=CD=5. The top base = 8 and the bottom base = 14. What is the... In an isosceles trapezoid ABCD, AB=CD=5. The top base = 8 and the bottom base = 14. What is the... What is a trapezoid? Which is always a rhombus? Parallelogram, Trapezoid, Rectangle, or Square? Why is a trapezoid a quadrilateral, but a quadrilateral is not always a trapezoid? What is the difference between a trapezoid and a rhombus? How do you prove this theorem on trapezoids and its median? The median (or mid-segment) of a... See all questions in Quadrilaterals Impact of this question 3915 views around the world You can reuse this answer Creative Commons License