1. Find the cost of levelling the ground in the form of a triangle having the sides 51 m, 37 m and 20 m at the rate of ₹ 3 per m².
a = 51 m, b = 37 m, c = 20 m
semiperimeter: p = (51+37+20):2 = 54 m
Area of triangle:

Rate: ₹ 3 per m².
Cost: ₹ 3•306 = ₹ 918
2. Find the area of the isosceles triangle whose perimeter is 11 cm and the base is 5 cm.
a = 5 cm
a+2b = 11 cm ⇒ 2b = 6 cm ⇒ b = 3 cm
p = 11:2 = 5.5

3. Find the area of the equilateral triangle whose each side is 8 cm.
a = b = c = 8 cm
p = (8•3):2 = 12 cm

4. The perimeter of an isosceles triangle is 32 cm. The ratio of the equal side to its base is 3 : 2. Find the area of the triangle.
a = 2x
b = 3x
2x + 2•3x = 32 cm ⇒ 8x = 32 cm ⇒ x = 4 cm ⇒ a = 8 cm, b = 12 cm
p = 32:2 = 16 cm

1000 millimeters = 100 centimeters
Answer:
22 rounds down to 20 if that is what you are asking
Step-by-step explanation:
You did not finish your question i dont think. 22 DOES round down to 20 though.
Find the area of the fabric
The fabric is circular, so we find the area using the area of circle formula
a = π × r²
input the numbers
a = π × r²
a = 3.14 × (1.2)²
a = 3.14 × 1.44
a = 4.5216 ft²
Calculate the total cost
Multiply the cost by the area
cost = 5.4 × 4.5216
cost = 24.417
The total cost is approximately $24.42
Answer:
x = 3√7
Step-by-step explanation:
From the right triangle given in the picture,
Altitude or height of the triangle (AD) = x
Base or hypotenuse of the given triangle (BC) = 16
Length of segment BD = 16 - 7 = 9
By using geometric mean theorem in the given triangle,

(AD)² = (BD)(CD)
x² = 9×7
x = √63
x = 3√7