11.4 Areas of Kites and Related Figures
A kite = A △ ABD + A △ DBC B C D Two formulas A DB = 10m AE = 5 m EC = 12 m BC = 13m <BAD is a right angle Find the area of the kite. E
Use correct formula A kite = A △ ABD + A △ DBC = ½ (BD)(AE) + ½(BD)(EC) = ½(10)(5) + ½ (10)(12) = = 85 m 2
T105: The area of a kite equals half the product of its diagonals. A kite = d 1 d 2 A kite = ½ (10)(17) = 85m 2
Find the area of a kite with diagonals 9 and 14 Draw, label, write all steps.
Find the area of a rhombus whose perimeter is 20 and whose longer diagonal is 8.
What do you know about the inside triangles? Remember: a rhombus is a parallelogram so the diagonals bisect each other. It is also a kite, so its diagonals are perpendicular to each other.
The area of a kite is 20. The longer diagonal is 8. Can you find the shorter diagonal?