SOLUTION: Jim stands beside a wide river and wonders how wide it is. He spots a large rock on the bank directly across from him. He then walks upstream d = 43 strides and judges that the ang

Question 828971: Jim stands beside a wide river and wonders how wide it is. He spots a large rock on the bank directly across from him. He then walks upstream d = 43 strides and judges that the angle between him and the rock, which he can still see, is now at an angle of 30∘ downstream. Jim measures his stride to be about 0.8 m long.
Estimate width of the river.
I understand d= 34.4 meters but after that im stuck
Found 2 solutions by rothauserc, LinnW:
Answer by rothauserc(4718) (Show Source): You can put this solution on YOUR website!
we have a right triangle and we want to find the width of the stream
note that the internal angle of the triangle where Jim is standing is
90 degrees - 30 degrees = 60 degrees, let w be the width of the stream therefore
tan 60 = w / 34.4
w = tan 60 * 34.4
w = 59.58 meters
width of stream is approximately 60 meters

Answer by LinnW(1048) (Show Source): You can put this solution on YOUR website!
We have a 30 60 90 triangle.
The ratio of the side lengths are
where 1/2 is opposite the 30 degree angle,
is opposite the 60 degree angle.
In our scenario, the short distance across the river
corresponds to the side opposite the 30 degree angle.
The distance along the bank, 34.4M , is the side opposite
the 60 degree angle.
We can set up proportion
==
where x represents the distance across the river.
So do cross products for =
=
divide each side by
=
multiply the right side by
=

RELATED QUESTIONS
a river runs directly east at 1.28 miles hour. if a swimmer can swim at the rate of 1.75... (answered by Alan3354)
a river runs directly east at 1.28 miles hour. if a swimmer can swim at the rate of 1.75... (answered by Boreal)
Ann is driving a motorboat across a river that 2 km wide. The boat has a speed of 20 km/h (answered by Theo)
(1) A swimmer is capable of swimming at 1.4m/s in still water. (a) how far downstream... (answered by josgarithmetic)
A swimmer is capable of swimming at 1.4m/s in still water (A) how far down the stream... (answered by ikleyn)
the diagram below shows part of the Limpopo river where it is wide and straight.A tall... (answered by Theo)
To find out how wide a river is, Jon and Sally mark an X at the spot directly across from (answered by KMST)
As David paddled his canoe across a 90-yd-wide river, the current carried him 40 yd... (answered by jim_thompson5910)
13. Atiba wants to measure the width of the Hudson River. Standing under a tree T on the... (answered by jim_thompson5910)