Question

2.
much rent did it pay?
122m
22m
120m
The triangular side walls of a flyover have been used for advertisements. The sides of
the walls are 122 m, 22 m and 120 m (see Fig. 12.9). The advertisements yield an
earning of 5000 per m² per year. A company hired one of its walls for 3 months. How​

Answer 1

Question: The triangular side walls of a flyover have been used for advertisements. The sides of the walls are 122 m, 22 m and 120 m. The advertisements yield an earning of 5000 per m² per year. A company hired one of its walls for 3 months. How much rent did it pay?

Answer: Rs. 16,50,000

Step by step explanation:

Let the sides of the walls be a, b and c respectively.

So, the sides of the walls : a = 122 m, b = 22 m & c = 120 m.

.°. Perimeter of triangular walls (s) = (a + b + c)/2

2s = 122 + 22 + 120

2s = 264 m²

s = 132 m²

Using Heron's Formula:

A = √[s(s - a) (s - b) (s - c)]

= √[132(132 - 122)(132 - 22)(132 - 120)]

= √[132 × 10 × 110 × 12]

= 12 × 11 × 10

= 1320 m²

Now,

The advertisements yield an earning of 5000 per m² per year. (Given)

Thus, earning on 1 m² area = Rs. 5000

Earning on 1320 m² area = 5000 × 1320

= Rs. 66,00,000

A company hired one of its walls for 3 months. (Given)

So, the rent for 3 months = 66,00,000 × 3/12

= Rs. 16,50,000

Therefore, the rent paid by the company for 3 months was Rs. 16,50,000.

Answer 2

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➣ Given

⭐ a = 122m

⭐ b = 22m

⭐ c = 120m

➣ Solution

☞ s = $\dfrac{</strong><strong>a</strong><strong> </strong><strong>+</strong><strong> </strong><strong>b</strong><strong> </strong><strong>+</strong><strong> </strong><strong>c</strong><strong> </strong><strong>}{</strong><strong>2</strong><strong>}$ (perimeter)

⟹ s = $\dfrac{122 + 22 + 120}{2}$

⟹ s = $\dfrac{264}{2}$

⟹ $\boxed{s = 132m}$

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☞ Now find the area with herons formula

$\sqrt{</strong><strong>s</strong><strong>(</strong><strong>s-a</strong><strong>)</strong><strong> </strong><strong>(</strong><strong>s-b</strong><strong>)</strong><strong> </strong><strong>(</strong><strong>s-c</strong><strong>)</strong><strong>}$

$\sqrt{132(132 - 122) (132 - 22) (132 - 120) }$

$\sqrt{132 × 10 × 110 × 12}$

⟹ $\boxed{1320m²}$

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☞ It is given that earning of 1 m² = 5000

Earning of 1320m² = 5000 × 1320 = Rs66,000,00

☞ Now we have to find the rent

⟹ so the rent for 3 months = $\dfrac{3}{12}$ × Rs66,000,00

⟹ Hence rent paid by company = Rs16,50,000

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