Question Details

From an interior point of an equilateral triangle, perpendiculars are drawn on all three sides. The sum of the lengths of the three perpendiculars is s. Then the area of the triangle is

Options

A

s23

B

3s22

C

3s23

D

s223

Show Answer

Correct Answer :

Option B

3s22

Solution :

The correct answer/option is:
3s22

Step-by-Step Explanation:

Let the equilateral triangle be ΔABC with side length a.
Let P be an interior point of the triangle. From P, perpendiculars of lengths p1, p2, and p3 are drawn to the three sides of the triangle.

The sum of the lengths of the three perpendiculars is given as:
s=p1+p>2+p3

By connecting the interior point P to the three vertices A, B, and C, we divide the main triangle into three smaller triangles: ΔPBC, ΔPCA, and ΔPAB.

The total area of ΔABC is equal to the sum of the areas of these three smaller triangles:
Area(ΔABC)=Area(ΔPBC)+Area(ΔPCA)+Area(ΔPAB)

Since the side length of the equilateral triangle is a, each sub-triangle has a base of length a and a height corresponding to one of the perpendiculars:
Area(ΔABC)=12ap1+12ap2+12ap3

Factoring out 12a, we get:
Area(ΔABC)=12a(p1+p2+p3)=12as

Using the relation for the sum of perpendiculars s and side length a in an equilateral triangle, we obtain the area in terms of the sum of the perpendiculars:
Area=3s22

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