The perimeter of a right angled triagle is 24 cm. If its hypotenuse is 10 cm then area of triangle
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• Given Perimeter of a triangle = 24 cm
• We know that perimeter of a ∆ = sum of all sides
=> 24 = first side + second side + third side
=> 24 = first side + second side + 10
=> 24 - 10 = first side + second side.
=> 14 = first side + second side.
• Now, Let the first side be 'x'.
• Then, second side = 14 - x
• Now, since it is a right angled triangle, we will use the Pythagoras' Theorem, according to which, square of hypotenuse = sum of square of other two sides.
=> [ (x)² + (14 - x)²] = (10)²
• Using identity : (a - b)² = a² + b² - 2ab -
=> [ (x²) + (14² + x² (- 2 × 14 × x))] = 100
=> x² + 196 + x² - 28x = 100
• Shifting 100 to LHS -
=> x² + 196 + x² - 28x - 100 = 0
• Rearranging the terms -
=> x² + x² - 28x + 196 - 100 = 0
=> 2x² - 28x + 96 = 0
• Taking 2 in common -
=> 2 [x² - 14x + 48] = 0
• Shifting 2 to RHS -
=> x² - 14 + 48 = 0 ÷ 2
=> x² - 14x + 48 = 0
• Using the method of midterm split -
=> x² - 8x - 6x + 48 = 0
=> x(x - 8) - 6(x - 8) = 0
=> (x - 6)(x - 8) = 0
• Using the zero product rule -
x = 6
or, x = 8
• Now, since 6 + 8 = 14, 6 cm and 8 cm is the measurement of first and second side respectively.
• So, first side = 6 cm
• Second side = 14 - 6 = 8 cm
• Now, area of a right angled triangle = half the product of the two sides of the triangle (leaving the hypotenuse)
• Then, area of the ∆
= ½ × 6 × 8
= 3 × 4
= 12 cm²
• Therefore, the area of the triangle = 12 cm².
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Thank you... ;-)
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