Wednesday

August 20, 2014

August 20, 2014

Posted by **Dana** on Saturday, July 21, 2012 at 5:13pm.

- math -
**MathMate**, Saturday, July 21, 2012 at 6:56pmThe key to solving this kind of problems is to draw a diagram, and name the unknowns. After that, state the formulas that relate the unknown(s). Some times at the end, only one unknown is left, and you can therefore solve the problem.

Let A be the end of the shadow, and C be the bottom of the pole on the slope.

D be a point directly below C on a horizontal plane at the same level as A (i.e. on a horizontal surface below the slope).

Let B be the top of the pole.

Let

The height of the pole is x (=distance CB).

The distance between C and D be y.

From the definition of sine, we have

CD=y=20 sin(8°) and

From the definition of cosine, we have

AD=20 cos(8°)

and from the definition of tangent,

BD=AD tan(17°).

Using the diagram,

x=BD-CD=AD tan(17°)-20sin(8°)

=(20cos(8°))tan(17°)-20sin(8°)

So everything is known and x can be calculated using a calculator.

I get x=5.9m.

**Related Questions**

algebra - A flagpole at a right angle to the horizontal is located on a slope ...

algebra 2 - A flagpole at a right angle to the horizontal is located on a slope ...

math - A flagpole and a building stands on the same horizontal level.From the ...

Precalculus - A woman standing on a hill sees a flagpole that she knows to be 60...

Precalculus - A woman standing on a hill sees a flagpole that she knows to be 60...

math - if Amy stands 36 feet from a flagpole and the angle formed from the top ...

geometry - Shalonda notices that when she stands next to the flagpole, she casts...

algebra 2 - a flagpole casts a 60 foot shadow when the angle of elevation of the...

math/trig - A flagpole casts a shadow 44 ft with the sun angle of elevation is ...

Math - A man standing 20 m from a tower estimates the angle of elavation of the ...