Question 1123733
Karen and David set out from home at the same time.
 Karen cycles due north 20km/h and David due east at 15km/h. 
FInd
a) how far apart they are in 1 hour
their routes form a right triangle, the hypotenuse is the dist between them
h = {{{sqrt(20^2+15^2)}}}
h = 25 km after 1 hr
:
b)after how many minutes they are 10km apart
Change the speeds to km/min
20/60 = .33 km/min
15/60 = .25 km/min
let the t = time in min for them to be 10km apart
{{{(.33t)^2 + (.25t)^2 = 10^2}}}
{{{.1111t^2 + .0625t^2 = 100}}}
{{{.1736t^2 = 100}}}
{{{t^2 = 100/.1736}}}
t^2 = 576
t = {{{sqrt(576)}}}
t = 24 min, they are 10 mi apart 
:
c) the bearing of Karen from David at any time
Find the angle (David's position) using the tangent tan(A) = {{{20/15}}} = 53 degrees
In relation to true north, 90-53 = 37 degrees,
the Bearing then  360 - 37 = 323 degrees is Karen from David