Question

The table given below contains some measures of the rectangle. Find the unknown values.

Answer 1

(i) Area of the rectangle = (length × breadth) sq unit.

Perimeter of a rectangle = 2(1 + b) units.

l = 5 cm

b = 8 cm

∴ p = 2 (l + b) cm = 2 (5 + 8) cm = 2 × 13 cm

p = 26 cm

Area = (l × b) cm² = (5 × 8) cm²

A = 40 cm²

(ii) l = 13 cm

p = 54 cm

Perimeter = 2 (l + b) units

54 = 2 (13 + b) cm

54/2 = 13 + b

27 = 13 + b

b = 27 – 13

b = 14 cm

Area = l × b sq. unit = 13 × 14 cm²

A = 182 cm²

(iii) b = 15 cm

p = 60 cm

p = 2 (l + b) units

60 = 2 (l + 15) cm

60/2 = l + 15

30 = l + 15

l = 30 – 15 .

l = 15 cm

Area = l × b unit² = 15 × 15 cm² = 225 cm²

A = 225 cm²

(iv) l = 10 m

Area = 120 sq metre

Area = l × b sq.m

120 = 10 × 6

b = 120/10

b = 12 m

Perimeter =2 (l + b) units = 2(10 + 12) units = 2 × 22 m

A = 44 m

(v) b = 4 feet.

Area = 20 sq. feet

Area = l × b sq .feet

20 = l × 4

l = 20/4 feet

l = 5 feet

Perimeter = 2 (l + b) units.

p = 2 (5 + 4) feet = 2 × 9

p = 18 feet

Completing the unknown values in the table.