11-2 areas of trapezoids, rhombi, and kites
DESCRIPTION
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. base. leg. leg. base. Definitions. A rhombus is a quadrilateral with four congruent sides. (All rhombuses are parallelograms.) - PowerPoint PPT PresentationTRANSCRIPT
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.
DefinitionsA 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
base
legleg
Classify each quadrilateral as a square, rectangle, rhombus, parallelogram or trapezoid.
trapezoid
rhombus,
parallelogram
rectangle, parallelogram
trapezoid
square, rectangle, rhombus, parallelogram
The area of a trapezoid is the product of half the sum of the bases (b1 and b2) and the height (h).
hbb
A2
21 hbbA 212
1
Find the area of the trapezoid
47.5 cm2
9
4.5
5.5
37.125
5 cm
14 cm
5 cm2
6
8
30
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
A. 288 ft2
B. 295.5 ft2
C. 302.5 ft2
D. 310 ft2
Find the area of the side of the pool outlined below.
Definitions
• Rhombus: a quadrilateral with all four sides congruent.
• Kite: a quadrilateral with exactly two pairs of consecutive congruent sides.
The area of a rhombus or kite is ½ of the product of diagonal 1 and diagonal 2.
p. 791
A. Find the area of the kite.
Area of a kite
d1 = 7 and d2 = 12
Answer: 42 ft2
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 7 + 7 or 14 in. and 9 + 9 or 18 in.
Answer: 126 in2
Area of a rhombus
Step 2 Find the area of the rhombus.
d1 = 14 and d2 = 18
Simplify.2
A. 48.75 ft2
B. 58.5 ft2
C. 75.25 ft2
D. 117 ft2
A. Find the area of the kite.
A. 45 in2
B. 90 in2
C. 180 in2
D. 360 in2
B. Find the area of the rhombus.
p. 792
Area Formulas
11-2 Assignment
Page 793, 8-16No formulas with
numbers in it, no credit