posted by Shane .
Two walkers set off at the same time from a crossroad and walk along flat straight roads inclined to each other at 68 degrees.If they both walk at a speed of 6km/h,find their distance apart 10 minutes later.
make a sketch, you should get an isosceles triangle with equal legs of 6(10/60) or 1 km, and vertex angle of 68°
let the base be 2x, and each of the base angles will be 56°
cos 56° = x/1
x = .55919..
2x = 1.118..
they will be 1.118 km apart
we could use the cosine law:
distance^2 = 1^1 + 1^2 - 2(1)(1)cos68°
= 2 - 2cos68° = 1.25078..
distance = √1.25078.. = 1.118 , same as above