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You have studied in Class IX that a median of a triangle divides it into two triangles of equal areas. Verify this result for \(\triangle \) ABC whose vertices are A (4, – 6), B (3, – 2) and C (5, 2).


Answer :

The vertices of triangle ABC are A(4,-6), B (3, – 2) and C (5, 2).

Let D be the mid-point of side BC of ∆ ABC. Therefore, AD is the median in ∆ ABC.



So, coordinates of D are ( \( \frac{3+5}{2} \ , \ \frac{-2+2}{2} \) )
Therefore, coordinates of D = (4,0)

Now,
Area of ∆ ABD = \( \frac{1}{2} \ | \ [4(-2-0) \ + \ 3(0+6) \ + \ 4(-6+2)] | \)
= \( \frac{1}{2} \ | \ [ -8 + 18 - 16] \ | \)
= \( |-3| \ = \ 3 \) sq. units

Similarly,
Area of ∆ ACD = \( \frac{1}{2} \ | \ [4(0-2) \ + \ 4(2+6) \ + \ 5(-6-0)] \ | \)
= \( \frac{1}{2} \ | \ [ -8 + 32 - 30] \ | \)
= \( |-3| \ = \ 3 \) sq. units

\(\therefore \) Clearly, Area of ∆ ABD = Area of ∆ ACD = 3 sq. units.

Hence, median of a triangle divides it into two triangles of equal areas.

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