Kinda confused buttttt anyone know this?
1 answer:
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Answer:
Speed of river's current = 5 mph
Step-by-step explanation:
Let 'd' be the distance covered
Let x be the speed of the rivers current
Speed upstream = 15-x
speed downstream = 15+x
Time = distance / speed
time upstream =
time downstream =
the ferry trip upstream takes twice as long as its return trip downstream
=
divide both sides by d
=
cross multiply
Add 2x on both sideds
subtract 15 from both sides and divide by 3
x=5
Speed of river's current = 5 mph
Answer:
88.7°
Step-by-step explanation:
First, visualize. Assuming that the tower is at a perfectly 90° angle to the ground, you have a right triangle. We will call this triangle ΔABC where A is where you are, B is the top of the tower, and C is the base of the tower. Now we know the following:
∠A = ?
∠B = ?
∠C = 90
a = 346346
b = 7777
c = ?
Note: Triangles are labeled with three pairs of letters: a, b and c and A, B and C. The lower case letters, a, b and c represent the sides, and the upper case letters are the angles that are directly opposite of those sides. (see attached reference)
c is easy, c is the hypotenuse, so you can use the following equation to find the hypotenuse:
a² + b² = c²
Rearranged:
c = ±
Substitute a and b:
c = ±
Comes out to ~346433.3 meters.
Now if we use the Law of Sines:
=
=
We can use c and a, since we're trying to find what angle A is, so the ratio is set up as:
=
Well we know that C = 90, and so sin(90) in degrees (as opposed to radians) is 1. So then the set of equations is now:
=
Cross Multiply to get rid of the fractions:
346346 = 346433.3 * sin(A)
Divide:
= sin(A)
Using a calculator, if you take the arcsin of that fraction, you will get what angle A is supposed to be:
arcsin( ) = ∠A = 88.7°
