Straight LineHardBloom L3

Question

In the adjacent figure $\bigtriangleup ABC$ is right angled at $B$. If $AB = 4$ and $BC = 3$ and side $AC$ slides along the coordinate axes in such a way that ' $B$ ' always remains in the first quadrant, then $B$ always lie on straight line:

Options

A.$y = x$
B.$3y = 4x$
C.$4y = 3x$
D.$x + y = 0$

Solution

Sol. [Key Concept: Right angle at $B$ with legs of fixed length sliding on the axes ⇒ $B$ traces the line $y = \frac{BC}{AB}x$.]

$tan\theta = \frac{3}{4}\ $ (from Fig.)

⇒ Slope of $OB = tan\left( \frac{\pi}{2} - \theta \right) = cot\theta$

⇒ Locus of $(h,k)$ is $\frac{k}{h} = \frac{4}{3}$

$$\Rightarrow 3y = 4x$$

Create a free account to view solution

View Solution Free
Topic: Straight Line·Practice all Straight Line questions

More Straight Line Questions