Which of the following statement(s) given below is / are TRUE? A: Cost of fencing a park in the shape of rhombus at the rate of Rs. 24 / m is Rs. 720 if area of park is 96 cm2 and ratio of diagonals of the park is 3 : 4. B: Length of perpendicular from a vertex of an equilateral triangle to opposite side is 6√3 cm of area of triangle is 36√3 cm2. C: Perimeter of an equilateral triangle of area 49√3 cm2 is 42 cm.
Which of the following statement(s) given below is / are TRUE? A: Cost of fencing a park in the shape of rhombus at the rate of Rs. 24 / m is Rs. 720 if area of park is 96 cm2 and ratio of diagonals of the park is 3 : 4. B: Length of perpendicular from a vertex of an equilateral triangle to opposite side is 6√3 cm of area of triangle is 36√3 cm2. C: Perimeter of an equilateral triangle of area 49√3 cm2 is 42 cm. Correct Answer B and C
GIVEN:
Three statements.
CONCEPT:
Mensuration
FORMULA USED:
Area of rhombus = (D1 × D2) / 2
Area of an equilateral triangle = √3a2 / 4
CALCULATION:
A:
Let diagonals of rhombus are ‘3x’ and ‘4x’ respectively.
Area of rhombus = (3x × 4x) / 2
96 = 6x2
⇒ x = 4
Side of rhombus = √ = 10 m
Perimeter of rhombus = 10 × 4 = 40 cm
Cost of fencing = 40 × 24 = Rs. 960
B:
Let side of triangle = ‘a’
Now,
√3a2 / 4 = 36√3
⇒ a = 12
Let length of perpendicular from a vertex = ‘x’
Now,
36√3 = (1 / 2) × x × 12
⇒ x = 6√3 cm
C:
Let side of triangle = ‘a’
Now,
√3a2 / 4 = 49√3
⇒ a = 14
Perimeter of triangle = 3a
= 42 cm
Hence, only statements B and C are TRUE.