Area & Perimeter | Answer Keys

Student Concept Worksheet Answers

1. Grid 6×4

24 square units

2. Rectangle 7 in × 3 in

Perimeter = 20 inches

3. Rectangle 9 cm × 5 cm

Area = 45 sq cm, P = 28 cm

4. Garden fence (12 ft × 8 ft)

Perimeter: 40 feet

5. Bulletin board (6 ft × 4 ft)

Area: 24 square feet

Practice Worksheet Answers

Part A: Count Squares

1. (4×3)

12 sq units

2. (5×2)

10 sq units

3. (7×4)

28 sq units

4. (3×5)

15 sq units

Part B: Area Formula

5. 9×5

45 sq cm

6. 8×8

64 sq in

7. 12×4

48 sq ft

8. 7×6

42 sq m

Part C: Perimeter

9. 10+4+10+4

28 cm

10. 7+7+7+7

28 in

11. 11+5+11+5

32 ft

12. 9+3+9+3

24 m

Part D: Both

13. 6 cm × 4 cm

A = 24 sq cm, P = 20 cm

14. Square 5 in

A = 25 sq in, P = 20 in

Part E: Composite Figures

15. L-shape

12 sq units (4+8)

16. L-shape

14 sq units (10+4)

Part F: Word Problems

17. Poster border

28 inches (perimeter)

18. Kitchen floor

63 sq feet (area)

19. Square garden fence

48 meters (perimeter)

20. Bedroom rug

20 sq feet (area)

FAST Practice Quiz Answers

B. 18 square units

Count: 6 × 3 = 18. Answer C is wrong because area is in SQUARE units, not just units.

B. 26 cm

Perimeter = 8 + 5 + 8 + 5 = 26 cm. Answer A only adds two sides. Answer C is area (40 sq cm). Answer D has wrong units.

D. 63 square feet

Carpet covers the INSIDE, so we need AREA: 9 × 7 = 63 square feet. Answers A and B are perimeter-related.

B. 9 square units

Count the squares: 5 in top row + 2 + 2 = 9 total. Or split: (5×1) + (2×2) = 5 + 4 = 9.

24 meters

Square means all sides equal: 6 + 6 + 6 + 6 = 24 meters.

B. 40 inches

Ribbon goes AROUND, so we need perimeter: 12 + 8 + 12 + 8 = 40 inches. Answer C is area.

A. 5 inches

Area = length × width. 35 = 7 × width. Width = 35 ÷ 7 = 5 inches.

D. Both B and C

B: 6 × 4 = 24 ✓. C: 12 × 2 = 24 ✓. A: 8 × 4 = 32 ✗. Both B and C work!

60 square inches

Area = 10 × 6 = 60 square inches.

Perimeter = 50 feet, Area = 150 square feet

Perimeter (fencing): 15+10+15+10 = 50 ft. Area (soil): 15 × 10 = 150 sq ft.

Scoring Guide

Assessment	Total Points	Proficient (70%+)	Needs Support
Student Concept Worksheet	5 points	4+ correct	Practice with manipulatives
Practice Worksheet	20 points	14+ correct	Focus on word problem clues
FAST Practice Quiz	10 points	7+ correct	Review area vs. perimeter distinction

Common Errors: Confusing area and perimeter, forgetting to add all 4 sides for perimeter, using wrong units (square vs. linear), counting grid lines instead of squares.