Question

2. Find the length of the rectangle if the perimeter
and width are :
(a) Perimeter = 86 cm, width = 18 cm
(b) Perimeter = 128 cm, width = 25 cm
(c) Perimeter = 151 cm, width = 29.5 cm​

Answer 1

Answer:

1. 86=2L+2B

86/2=L+B

43=L+18

43-18=L

25=L

Answer 2

Required solution:

Part a:

Given:

• Perimeter = 86 cm
• Width = 18 cm

Let:

• length= x

We know:

Perimeter = 2 ( Length + width)

by using this formula we can find value of length

• Perimeter = 2 ( Length + width)

• 86 = 2 ( x + 18)

• 86 = [2 × x] + [18 × 2]

• 86 = 2x + 36

• 86 - 36 = 2x

• 50 = 2x

• x = 50/2

• x = 25 cm

Verification :

• 86 = 2 ( x + 18)

• 86 = 2(25 + 18)

• 86 = 2(43)

• 86 = 86

hence verified!

.°. value of length = 25 cm

Part b:

Given:

• Perimeter = 128 cm
• Width = 25 cm

Let:

• length= x

We know:

Perimeter = 2 ( Length + width)

by using this formula we can find value of length

• Perimeter = 2 ( Length + width)

• 128 = 2 (25 + x)

• 128 = [25 × 2]+[2 × x]

• 128 = 50 + 2x

• 128 - 50 = 2x

• 78 = 2x

• 78/2 = x

• x = 39 cm

Verification :

• 128 = 2 (25 + x)

• 128 = 2 (25 + 39)

• 128 = 2(64)

• 128 = 128

Hence verified!

.°. value of length = 39 cm

part c:

Given:

• Perimeter = 151cm
• Width = 29.5 cm

Let:

length= x

We know:

Perimeter = 2 ( Length + width)

by using this formula we can find value of length

• Perimeter = 2 ( Length + width)

• 151 = 2 ( x + 29.5)

• 151 =[ 2 × x] +[29.5 × 2]

• 151 = 2x + 59

• 151 - 59 = 2x

• 92 = 2x

• 92/2 = x

• x = 46 cm

Verification:

• 151 = 2 ( x + 29.5)

• 151 = 2( 46 + 29.5)

• 151 = 2( 75.5 )

• 151 =151

Hence verified!

.°. value of length = 46 cm