Coordinate Geometry Question 144
Question: The area of the triangle with vertices at $ (-4,1),(1,2),(4,-3) $ is
[EAMCET 1980]
Options:
A) 14
B) 16
C) 15
D) None of these
Show Answer
Answer:
Correct Answer: A
Solution:
Area of triangle $ =\frac{1}{2}| \begin{vmatrix} x_1 & y_1 & 1 \\ x_2 & y_2 & 1 \\ x_3 & y_3 & 1 \\ \end{vmatrix} | $
$ =\frac{1}{2}| \begin{vmatrix} -4 & 1 & 1 \\ 1 & 2 & 1 \\ 4 & -3 & 1 \\ \end{vmatrix} | $
= $ \frac{1}{2}[-4(2+3)-1(1-4)+1(-3-8) $
$ =\frac{1}{2}|-28|=14 $ units.
BETA
