Question

40. The edges of a triangular board are 12 cm, 16 cm and 20 cm. It is to be painted on both sides. The cost of painting it @ 25 paise per cm' is (a) Rs 36 (b) Rs 96 (c) Rs 24 (d) Rs 48​

Answer 1

Answer:

Rs 96 is the confirm answer

Answer 2

Given:

The edges of a triangular board are 12 cm, 16 cm and 20 cm. It is to be painted on both sides. The cost of painting it @ 25 paise per cm' is?

To find:

The cost of painting it @ 25 paise per cm' is?

Solution:

Finding the area of the board that needs to be painted:

Here we have the dimensions of the triangular board as

a = 12 cm

b = 16 cm

c = 20 cm

By using Heron's formula, we get

Semi-Perimeter, S = $\frac{12 + 16+ 20}{2} = \frac{48}{2} = 24$

Area of on side of the triangular board is,

= $\sqrt{S (S - a )(S - b)(S - c)}$

= $\sqrt{24 (24 - 12 )(24 - 16)(24 - 20)}$

= $\sqrt{24 \times 12 \times 8 \times 4}$

= $\sqrt{9216}$

= $96\:cm^2$

Since it is to be painted on both sides

∴ The area of both sides of the board = 96 cm² × 2 = 192 cm²

Finding the cost of painting both sides:

If the cost of painting 1 cm² of the board = Rs. 0.25

Then,

The cost of painting a 192 cm² triangular board is,

= 192 cm² × Rs. 0.25/cm²

= Rs. 48 ← option (d)

Thus, the cost of painting it @ 25 paise per cm² is → Rs. 48.

----------------------------------------------------------------------------------------------------

Also View:

the cost of painting the top surface of a triangular board at 80 paise per metre square is Rs. 176.40. If the height of the board measures 24.5 find its base?

brainly.in/question/2017072

If the edges of a triangular board are 15 cm, 36 cm and 39cm, then the cost of painting it's one of the faces at the rate of 5 paise per cm square is?

brainly.in/question/3614136

The edge of a triangular board are 6cm,8cm,10cm calculate the cost of painting it as the rate of 9paise per cm²

brainly.in/question/8717205