Q. Orthocentre of triangle with vertices (0, 0), (3, 4) and (4, 0) is

A) $(3,\ 5/4)$
B) (3, 12)
C) (3, 3/4)
D) (3, 9)
Explanation

(c)
Now, we take $BD\bot AC$ and $AE\bot BC$
[image:10_image39.emf]
Slope of $BD = - \frac{3}{4}$
$Equation\ of\ BD,\ y - 0 = \frac{- 3}{4}(x - 4)$
$\Rightarrow 4y = - 3x + 12$
$\Rightarrow 3x + 4y - 12 = 0$ …(i)
and slope of $AE = \frac{1}{4}$
$\therefore Equation\ of\ AE,\ y - 0 = \frac{1}{4}(x - 0)$
$\Rightarrow x - 4y = 0$ …(ii)
On solving Eqs. (i) and (ii), we get
$x = 3,\ \ y = \frac{3}{4}$
$\therefore Orthocentre\ of\ the\ traingle\ is\ \left( 3,\frac{3}{4} \right)$

Dr. Abubacker
Reviewed by Dr. Abubacker

Physics Educator & NEET/JEE Specialist

Ph.D. in Physics with 19+ years of teaching experience.