This handy Math in Focus Grade 4 Workbook Answer Key Chapter 12 Practice 4 Composite Figures detailed solutions for the textbook questions.

## Math in Focus Grade 4 Chapter 12 Practice 4 Answer Key Composite Figures

**Find the lengths of the unknown sides of each figure. Then find the perimeter of each figure.**

**Example**

Length of first unknown side = 16 – 4 = 12 in.

Length of second unknown side = 13 + 4 = 17 in.

Perimeter of figure = 16 + 13 + 12 + 4 + 4 + 17 = 66 in.

Perimeter = 66 in.

Question 1.

Perimeter = ____________ yd

Answer:

Length of first unknown side = **6 yards**

Length of second unknown side = 24 yards – 8 yards – 5 yards =** 11 yards
**Perimeter of figure = 5 yd + 6 yd + 8 yd + 3 yd + 24 yd + 3 yd + 11 yd +6 yd

= 66 yd

Perimeter = 66 yd.

Perimeter = 66 yd.

**Solve. Show your work.**

Question 2.

Tom wants to fence in the piece of land shown in the diagram. Find the perimeter of the piece of land to find the length of fencing material he needs.

Perimeter = __________ m

Answer:

Length of first unknown side = 8 m

Length of second unknown side = 9 m

Length of third unknown side = 3m

Perimeter of the piece of land = 3 m + 8 m + 12 m + 8 m + 9 m + 3 m + 3 m = 46 m

Perimeter = **46 m
**He needs

**46 m**of fencing material.

Question 3.

Find the perimeter of this figure.

Perimeter = ___________ mi

Answer:

Length of first unknown side ST = **28 mi – 12 mi = 16 mi**

Length of second unknown side TU = **24 mi – 6 mi = 18 mi**

Perimeter of the figure = 28 mi + 6 mi + 16 mi + 18 mi + 12 mi + 24 mi = 104 mi

Perimeter = **104 mi**

**Solve. Show your work.**

Question 4.

Find the perimeter of the figure.

Perimeter = ___________ cm

Answer:

Perimeter of the figure = 42 cm + 18 cm + 34 cm + 42 cm + 16 cm = 152 cm

Perimeter = **152 cm**

**Find the area of each composite figure. Show your work.**

**Example**

Break up the figure into two rectangles as shown. Then find the area of the whole figure.

Area of rectangle 1 = length × width

= 10 × 3

= 30 in.^{2}

Area of rectangle 2 = length × width

= 7 × 6

= 42 in.^{2}

Total area = area of rectangle 1 + area of rectangle 2

= 30 + 42

= 72 in.^{2}

Area = 72 in.^{2}

**Find the area of each composite figure. Show your work.**

Question 5.

Area = ____________ ft^{2}

Answer:

For rectangle 1

length = 22 feet

Width = 18 feet

Area of rectangle 1 = length × width

= 22 feet × 18 feet

= **396 ft ^{2}**

For rectangle 2

length = 14 feet

width = 9 feet

Area of rectangle 2 = length × width

= 14 feet × 9 feet

=

**126 ft**

^{2}Total area = area of rectangle 1 + area of rectangle 2

= 396 ft

^{2}+ 126 ft

^{2 }= 522 ft

^{2}

**Area =522 ft**

^{2}Question 6.

Area = __________ m^{2}

Answer:

Explanation:

For rectangle 1

length = 12 m

Width = 5 m

Area of rectangle 1 = length × width

= 12 m × 5 m

= **60 m ^{2}**

For rectangle 2

length = 8 m

width = 3 m

Area of rectangle 2 = length × width

= 8 m × 3 m

=

**24 m**

^{2}Total area = area of rectangle 1 + area of rectangle 2

= 60 m

^{2}+ 24 m

^{2 }=84 m

^{2}

**Area =84 m**

^{2}