Question

Find the point that divides A(2, 4) and B(6, 8) in the ratio a : 1.

• A. $(\frac{6a+1}{a+1},\frac{8a+4}{a+1})$
• B. $(\frac{6a+2}{a+1},\frac{8a+4}{a+1})$
• C. $(\frac{6+2a}{a+1},\frac{8+4a}{a+1})$
• D. $(\frac{6a+8}{a+1},\frac{2a+4}{a+1})$

Answer 1

The correct option is B

$(\frac{6a+2}{a+1},\frac{8a+4}{a+1})$

The point, say P(x, y), divides the line AB into the ratio a : 1. The formula for the point that divides a line in the ratio m : n is,
$(\frac{(n\times x_1+m\times x_2)}{m+n},\frac{n\times y_1+m\times y_2}{m+n})$
Where $(x_1,y_1)and(x_2,y_2)$ are the coordinates of the endpoints of the line segment AB
Applying the formula, we get $(\frac{(1\times 2+a\times 6)}{a+1},\frac{1\times 4+a\times 8}{a+1})=(\frac{6a+2}{a+1},\frac{8a+4}{a+1})$