# Trigonometry - Angle Of Elevation

• Sep 2nd 2010, 10:01 PM
liukawa
Trigonometry - Angle Of Elevation
Hi guys.

Am currently stuck with this question asking me to find the greatest possible angle of elevation..

Need help urgently thanks !

Attachment 18810
• Sep 2nd 2010, 10:47 PM
undefined
Quote:

Originally Posted by liukawa
Hi guys.

Am currently stuck with this question asking me to find the greatest possible angle of elevation..

Need help urgently thanks !

It's unclear whether the BC at the end means line or line segment. Possibly it won't matter, I haven't run the numbers. Anyway find the point on BC that is closest to A, call the point P, then look at triangle PAD.

Of interest is whether angle ABC is acute, obtuse, or right.
• Sep 2nd 2010, 11:02 PM
liukawa
Quote:

Originally Posted by undefined
It's unclear whether the BC at the end means line or line segment. Possibly it won't matter, I haven't run the numbers. Anyway find the point on BC that is closest to A, call the point P, then look at triangle PAD.

Of interest is whether angle ABC is acute, obtuse, or right.

How to find point P that is closest to A.

ABC is an acute angle - 84 degree
• Sep 2nd 2010, 11:22 PM
undefined
Quote:

Originally Posted by liukawa
How to find point P that is closest to A.

ABC is an acute angle - 84 degree

Rounded to nearest degree, yes 84. So it doesn't matter whether they meant BC line or line segment.

To find shortest distance from a line L to a point Q, look at line M perpendicular to L through Q.

In other words, drop an altitude from A to BC.
• Sep 2nd 2010, 11:25 PM
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Note: You can save yourself some time by using that area of a triangle (using the usual letters) is (1/2)absinC and also (1/2)bh^2.