1. 11-2 Areas of Trapezoids, Rhombi, and Kites
You found areas of triangles and parallelograms.
Find areas of trapezoids.
Find areas of rhombi and kites.

2. Definitions A rhombus is a quadrilateral with four congruent sides.
(All rhombuses are parallelograms.)
A trapezoid is a quadrilateral with exactly one pair of parallel sides. The parallel sides are the bases of the trapezoid, and the nonparallel sides are its legs.
base
leg

3. Classify each quadrilateral as a square, rectangle, rhombus, parallelogram or trapezoid.
rectangle, parallelogram
trapezoid
square, rectangle, rhombus, parallelogram
trapezoid
rhombus,
parallelogram

4. The area of a trapezoid is the product of half the sum of the bases (b1 and b2) and the height (h).

5. Find the area of the trapezoid9
4.5
5.5
5 cm
14 cm 2 6 8
37.125
47.5 cm2 30

6. SHAVING Find the area of steel used to make the side of the razor blade shown below.
Area of a trapezoid
h = 1, b1 = 3, b2 = 2.5
Simplify.
Answer: A = 2.75 cm2

7. Find the area of the side of the pool outlined below.
A. 288 ft2
B ft2
C ft2
D. 310 ft2

8. Definitions Rhombus: a quadrilateral with all four sides congruent.
Kite: a quadrilateral with exactly two pairs of consecutive congruent sides.

9. The area of a rhombus or kite is ½ of the product of diagonal 1 and diagonal 2.
p. 791

10. A. Find the area of the kite.
Area of a kite
d1 = 7 and d2 = 12
Answer: 42 ft2

11. B. Find the area of the rhombus.
Area of a Rhombus and a Kite
B. Find the area of the rhombus.
Step 1 Find the length of each diagonal.
Since the diagonals of a rhombus bisect each other, then the lengths of the diagonals are or 14 in. and or 18 in.
Step 2 Find the area of the rhombus.
Area of a rhombus
d1 = 14 and d2 = 18
Simplify. 2
Answer: 126 in2

12. A. Find the area of the kite.
A ft2
B ft2
C ft2
D. 117 ft2

13. B. Find the area of the rhombus.
A. 45 in2
B. 90 in2
C. 180 in2
D. 360 in2

14. Area Formulas
p. 792

15. No formulas with numbers in it, no credit
11-2 Assignment
Page 793, 8-16
No formulas with numbers in it, no credit