Question

An 80-mile trip is represented on a gridded map by a directed line segment from point M(3, 2) to point N(9,

13). What point represents 60 miles into the trip? Show your work and explain your reasoning.

Answer 1

Explanation:

If the distance from M to N is 80 miles and we want to find the coordinates of the point 60 miles into the trip, we are looking for the point 3/4 of the way from M to N, since 60 is 3/4 of 80. This is the process:

First we need to consider that MN is a directed vector. We first find the components of the directed vector, which is found in the change in x and the change in y. First step, then, looks like this:

<Δx, Δy> = <9-3, 13-2> = <6, 11> We will call those the x and y components of the vector (which comes from vector study in both physics and math, so if you don't understand that, it's ok! Just follow the process here and you'll be fine). Knowing that 60 is 3/4 of the way from M to N, we find 3/4 of both the x and y components, like this:

`<(3)/(4)(6), (3)/(4)(11)>` which will give us 3/4 of the change in x and 3/4 of the change in y:

`<(18)/(4),(33)/(4)>=<4.5,8.25>`

Since we are going 3/4 of the way from M to N, we add that component to the x and y coordinates of M, giving us 3/4 of the way from M to N, which translates to 60 miles of the 80 mile trip:

(3 + 4.5, 2 + 8.25) = (7.5, 10.25)

Those are the coordinates of the point that represents 60 miles into the 80 mile trip.