Answer:
-40 I wanna say
Step-by-step explanation:
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

Seventy- two thousand three hundred twelve
Lets write this out:-
2.4 + 0.8 = ________ + 1.21 = ______ + 1.78 = ______ - 5.14 = _____
So to solve d blanks we will do d following:-
2.4 + 0.8 = 3.2
Now lets write this out AGAIN.
2.4 + 0.8 = 3.2 + 1.21 = ______ + 1.78 = ______ - 5.14 = ____
Now lets solve again:-
3.2 + 1.21 = 4.41
Now lets write this out AGAIN.
2.4 + 0.8 = 3.2 + 1.21 = 4.41 + 1.78 = ______ - 5.14 = ____
Now lets solve again:-
4.41 + 1.78 = 6.19
Now lets write this out AGAIN.
2.4 + 0.8 = 3.2 + 1.21 = 4.41 + 1.78 = 6.19 - 5.14 = ____
Now lets solve again:-
6.19 - 5.14 = 1.05
Now lets write this out AGAIN.
2.4 + 0.8 = 3.2 + 1.21 = 4.41 + 1.78 = 6.19 - 5.14 = 1.05
So, 2.4 + 0.8 = 3.2 + 1.21 = 4.41 + 1.78 = 6.19 - 5.14 = 1.05
Hope I helped ya!! xD
Hope this helps with the answer to your question :)