28) The areas of a square and a rectangle are equal
The length of the rectangle is greater than the
length of any side of the square by 5 cm and
the breadth is less by 3 cm. Find the perimeter
of the rectangle
(a) 17 cm
(b) 26 cm
(C) 30 cm
(d) 34 cm
Answers
26 cm
Step-by-step explanation:
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★ Given:
The areas of a square and a rectangle are equal.
The length of the rectangle is greater than the side of the square by 5 cm.
The breadth of the rectangle is less than the side of the square by 3 cm.
★ To Find:
The perimeter of the rectangle.
★ Formulae to be used:
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★ Solution
Let the side of the square be a.
So, length of the rectangle = a + 5
Breadth of the rectangle = a - 3
It is given that the area of the square and the rectangle are equal.
Area of the square = a²
Area of the rectangle = lb
Forming an equation from the statements:
a² = lb
→ Providing the values of the variables.
a² = (a + 5)(a - 3)
→ Distributing the values:
= a² = a x (a - 3) + 5 x (a -3)
= a² = a² - 3a + 5a - 15
→ Combining the like terms:
= a² = a² + 2a - 15
→ Moving the like terms to the LHS:
= a² - a² -2a - 15
= 0 = -2a - 15
→ Moving the constant term to the LHS:
= 15 = 2a
a = 15/2
a = 7.5
Now:
Length of the rectangle = a + 5
= 7.5 + 5
= 12.5 cm
Breadth of the rectangle = a - 3
= 7.5 - 3
= 4.5 cm
Perimeter of rectangle = 2 (l+ b)
= 2 (12.5 + 4.5)
= 2 x 17
= 34 cm
Hence the required correct option is Option D: 34 cm.
Knowledge Bytes:
→ Square
Please refer the first attachment to view the latex figure.
✳ A square is a quadrilateral with all the four sides as equal and parallel. All the angles of a square are right angled.
→ Rectangle
Please refer the second attachment to view the latex figure.
✳ A rectangle is a quadrilateral with the opposite pairs of sides as equal and parallel. All the angles of a rectangle are equal.