Posted by Anonymous on .
I don't understand this,so can you please explain more clearly. Where did you get the 1/5?
1.The point P divides the interval joining A(1,2) to B(9,3) internally in the ratio 4:1. Find the coordinates of P.

MATH 
Kuai,
(4*9+ 1*2)/(4+1), (4*3 + 1*2)/(4+1)
((362)/5, (122)/5))
(34/5, 10/5)
(34/5, 2) or (6.4, 2) 
MATH 
Steve,
eh?
since the line is divided into ratio 4:1, you can consider it divided into fifths. P is 4/5 of the way along the line. That means its xcoordinate is 4/5 of the way from 1 to 9, and its ycoordinate is 4/5 of the way from 2 to 3.
The distance from 1 to 9 is 9(1) = 10.
4/5 of 10 is 8
Similarly for y, 4/5 of the way from 2 to 3 is 4.
So starting at A, add 8 to x and 4 to y to get
P = (7,2)