Answer:
Given:
- The length of the rectangular shaped lamina is 5 cm more than the length of the square shaped lamina.
- The breadth of the rectangular shaped lamina is 3 cm less than the length of the square shaped lamina.
- x = side length of square
i) Length of rectangular shaped lamina = (x + 5) cm
ii) Breadth of rectangular shaped lamina = (x - 3) cm
ii) Area of a rectangle = length × breadth
⇒ area of rectangular shaped lamina = (x + 5)(x - 3) cm²
Given:
- area of rectangular shaped lamina = 105 cm²
⇒ (x + 5)(x - 3) = 105
Expand:
⇒ x² - 3x + 5x - 15 = 105
Combine like terms:
⇒ x² + 2x - 15 = 105
Subtract 105 from both sides:
⇒ x² + 2x - 120 = 0
iv) Solve x² + 2x - 120 = 0
Rewrite:
⇒ x² + 12x - 10x - 120 = 0
Break into groups:
⇒ (x² + 12x) - (10x + 120) = 0
Factorize the parentheses:
⇒ x(x + 12) - 10(x + 12) = 0
Factor out common term:
⇒ (x - 10)(x + 12) = 0
Therefore,
x - 10 = 0 ⇒ x = 10
x + 12 = 0 ⇒ x = -12
As length is positive, x = 10 only
Therefore,
Length of rectangular shaped lamina = 15 cm
Breadth of rectangular shaped lamina = 7 cm