Page 145 - NUMINO TG_6A
P. 145
Activity 2 Areas of Different Shapes
jOb ective Find the areas of different shapes.
1. Textbook Instructions Activity 2 Areas of Different Shapes
Students will use what they have learned to Have students find the area of the shape by summing up the areas of the figures within the shape.
find the area of complex figures. They should be able to find the rest of the dimensions using the given dimensions .
1. Have the students look at the figures, 1 . Find the area of each colored figure.
separate them into familiar shapes, and find
the areas. The area can be found by adding Area of the 3.14 7 7 1 76.93 (cm2)
the areas of each shape. 2
Example: Red figure
20 cm Area of the = 14 20 = 280 (cm2 )
Find the sum of the areas of a semicircle with Area of the
a 14 cm diameter ( ) and a rectangle with a 76.93 280 356.93 (cm2)
20 cm length and 14 cm width ( ).
1a. Two quarter circles: 4 yd radius 14 cm
One rectangle: 6 yd length, 4 yd width a. Area of the 3.14 4 4 1 12.56 (yd2)
1b. One quarter circle: 2 ft radius Area of the 4
6 yd 4 yd
One square: 2 ft length = 6 4 = 24 (yd2)
One rectangle: 4 ft length, 2 ft width b.
1c. One semicircle: 4 m diameter (2 m radius) Area of the
One quarter circle: 4 m radius 2 ft
One triangle: 4 m base, 4 m height 2 ft 12.56 24 12.56 49.12 (yd2)
4 ft
Area of the = 2 2 = 4 (ft2) 1 3.14 (ft2)
c. Area of the 3.14 2 2 4
Area of the
4m Area of the = 2 4 = 8 (ft2)
4m
Area of the 4 3.14 8
78 Area of the 15.14 (ft2)
Area of the
Area of the 3.14 2 2 1 6.28 (m2)
2
=4 4 1 = 8 (m2)
2
3.14 4 4 1 12.56 (m2)
4
6.28 8 12.56
26.84 (m2)
2. Build Understanding
Problem: Find the area of Solution: Find the sum of the areas for:
the colored figure.
Semicircle with 3 cm radius ( ), Semicircle with 4 cm radius ( ),
Semicircle with 5 cm radius ( ), Triangle with 6cm base, 8 cm height ( )
3.14 3 3 1 14.13 (cm2)
2
10 cm 3.14 4 4 1 25.12 (cm2)
2
8 cm
3.14 5 5 1 39.25 (cm2)
2
6 cm 68 1 24 (cm2)
2
128 NUMINO Teacher s Guide
14.13 25.12 39.25 24 102.5 (cm2)
Answer: 102.5 cm2
jOb ective Find the areas of different shapes.
1. Textbook Instructions Activity 2 Areas of Different Shapes
Students will use what they have learned to Have students find the area of the shape by summing up the areas of the figures within the shape.
find the area of complex figures. They should be able to find the rest of the dimensions using the given dimensions .
1. Have the students look at the figures, 1 . Find the area of each colored figure.
separate them into familiar shapes, and find
the areas. The area can be found by adding Area of the 3.14 7 7 1 76.93 (cm2)
the areas of each shape. 2
Example: Red figure
20 cm Area of the = 14 20 = 280 (cm2 )
Find the sum of the areas of a semicircle with Area of the
a 14 cm diameter ( ) and a rectangle with a 76.93 280 356.93 (cm2)
20 cm length and 14 cm width ( ).
1a. Two quarter circles: 4 yd radius 14 cm
One rectangle: 6 yd length, 4 yd width a. Area of the 3.14 4 4 1 12.56 (yd2)
1b. One quarter circle: 2 ft radius Area of the 4
6 yd 4 yd
One square: 2 ft length = 6 4 = 24 (yd2)
One rectangle: 4 ft length, 2 ft width b.
1c. One semicircle: 4 m diameter (2 m radius) Area of the
One quarter circle: 4 m radius 2 ft
One triangle: 4 m base, 4 m height 2 ft 12.56 24 12.56 49.12 (yd2)
4 ft
Area of the = 2 2 = 4 (ft2) 1 3.14 (ft2)
c. Area of the 3.14 2 2 4
Area of the
4m Area of the = 2 4 = 8 (ft2)
4m
Area of the 4 3.14 8
78 Area of the 15.14 (ft2)
Area of the
Area of the 3.14 2 2 1 6.28 (m2)
2
=4 4 1 = 8 (m2)
2
3.14 4 4 1 12.56 (m2)
4
6.28 8 12.56
26.84 (m2)
2. Build Understanding
Problem: Find the area of Solution: Find the sum of the areas for:
the colored figure.
Semicircle with 3 cm radius ( ), Semicircle with 4 cm radius ( ),
Semicircle with 5 cm radius ( ), Triangle with 6cm base, 8 cm height ( )
3.14 3 3 1 14.13 (cm2)
2
10 cm 3.14 4 4 1 25.12 (cm2)
2
8 cm
3.14 5 5 1 39.25 (cm2)
2
6 cm 68 1 24 (cm2)
2
128 NUMINO Teacher s Guide
14.13 25.12 39.25 24 102.5 (cm2)
Answer: 102.5 cm2