Question

The area of the equilateral triangle is 20 √3 cm² then the length of each side is? (a) 8 cm (b) 16 cm (c) 16√3 cm (d) 4√5 cm

Answer 1

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✤ Required Answer:

✒ GiveN:

• Area of equilateral triangle = 20√3 cm²

✒ To FinD:

Length of each side of the triangle....?━━━━━━━━━━━━━━━━━━━━

✤ How to solve?

For solving the above question, I.e. to find the length of each side of the equilateral triangle, we need to know the know the special area formula of equilateral triangle.

$\large{ \boxed{ \rm{Area \: of \: eq. \: \triangle = \frac{ \sqrt{3} }{4} \times (side) {}^{2} }}}$

In this question, we are provided with the area of the equilateral triangle, so we can find the length of it side..

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✤ Solution:

We have,

• Area of eq. triangle = 20√3 cm²

So, By using formula,

➙ Area of eq. triangle = √3/4 × (side)²

➙ 20√3 = √3/4 × (side)²

➙ (side)² = 20√3 × 4/ √3

➙ (side)² = 80 cm²

➙ side = √80 cm

➙ side = 4√5 cm

✒ Therefore, Side of eq. triangle = 4√5 cm.

✒ Hence, solved!!━━━━━━━━━━━━━━━━━━━━

Answer 2

Answer:

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✤ Required Answer:

✒ GiveN:

Cost price of a fan = Rs. 1200

Gain % = 8 %

✒ To Find:

Selling price of the fan....?

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✤ How to solve?

For solving this question, Let's note down some important formulae:

Selling price = Cost price + Gain/Profit

And, Profit % = Profit/CP × 100

Or else, Direct formula,

\large{ \boxed{ \rm{SP = \frac{CP(100 + p\%)}{100} }}}

SP=

100

CP(100+p%)

☃️ So, Let's try both the formulae, and solve the question

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✤ Solution:

Method 1:

We have,

Cost price = Rs. 1200

Gain % = 8 %

Finding gain/profit,

➝ Gain % = Gain/CP × 100

➝ 8 = Gain/1200 × 100

➝ 8 = Gain/12

➝ Gain = Rs. 96

Finding Selling price,

➝ Selling price = Cost price + Gain

➝ Selling price = Rs. 1200 + Rs. 96

➝ Selling price = Rs. 1296

☀️ Selling price of the fan = Rs. 1296

Method 2:

By using shortcut formula,

➝ Selling price = Cost price(100 + Gain%)/100

➝ Selling price = 1200(100 + 8)/100

➝ Selling price = 12 × 108

➝ Selling price = Rs. 1296

☀️ Here also, SP of the fan = Rs. 1296 only.

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