Sum of the areas of two squares is 468 m square if the difference of their perimeter is 24 m find the sides of the two square .
Answers
Let the sides of the first and second square be X and Y . Area of the first square = (X)²
Area of the second square = (Y)²
According to question, (X)² + (Y)² = 468 m² ——(1).
Perimeter of first square = 4 × X and Perimeter of second square = 4 × Y
According to question,
4X – 4Y = 24 ——–(2)
From equation (2) we get,
4X – 4Y = 24, 4(X-Y) = 24
X – Y = 24/4 , X – Y = 6
X = 6+Y ———(3)
Putting the value of X in equation (1)
(X)² + (Y)² = 468, (6+Y)² + (Y)² = 468
(6)² + (Y)² + 2 × 6 × Y + (Y)² = 468
36 + Y² + 12Y + Y² = 468
2Y² + 12Y – 468 +36 = 0
2Y² + 12Y -432 = 0
2( Y² + 6Y – 216) = 0
Y² + 6Y – 216 = 0
Y² + 18Y – 12Y -216 = 0
Y(Y+18) – 12(Y+18) = 0 (Y+18) (Y-12) = 0
(Y+18) = 0 Or (Y-12) = 0 Y = -18 OR Y = 12
Putting Y = 12 in EQUATION (3)
X = 6+Y = 6+12 = 18
- Side of first square = X = 18 m
- Side of second square = Y = 12 m.
SOLUTION
Let, Sides of the first and second square be S₁ and S₂
- Area of the first square = (S₁)²
- Area of the second square = (S₂)²
According to Question
(S₁)² - (S₂)² = 468 m² _(1)
- Perimeter of first square = 4 S₁
- Perimeter of second square = 4 S₂
According to question
4 S₁ - 4 S₂ = 24 _(2)
From equation (2) we get,
4 S₁ - 4 S₂ = 24
S₁ - S₂ = 6
S₁ = 6 + S₂
Putting the value of S₁ in equation (1)
- (S₁)² + (S₂)² = 468, (6+S₂)² + (S₂)² = 468
- (6)² + (S₂)² + 2 × 6 × S₂ + (S₂)² = 468
- 36 + S₂² + 12 S₂ + S₂ ² = 468
- 2S₂ ² + 12 S₂ - 432 = 0
- S₂ ² + 6 S₂ – 216 = 0
- S₂ ² + 18 S₂ – 12 S₂ - 216 = 0
- S₂(S₂ + 18) – 12(S₂ + 18) = 0
- (S₂ + 18) (S₂ - 12) = 0
- S₂ = -18 or 12
Putting S₂ = 12 in Eqn (3)
S₁ = 6 + S₂ = 18
Side of first square = S₁ = 18 m
Side of second square = S₂ = 12 m