ACT Math 3.1 Trigonometry
ACT Math: Trigonometry Drill 3, Problem 1. What is side DE?
|Foreign Language||Arabic Subtitled|
|Geometry||Right Triangles and Trigonometry|
|Product Type||ACT Math|
|Trigonometry||Solving right triangles|
Trigonometric relations in right triangles
But if we do recognize it, then we know that this angle is 90 degrees... F here is 60 degrees...
and E here is 30 degrees.
We should know that the ratio of the sides of a 30-60-90 triangle is 1 to square root
of 3 to 2.
If we label each side we have 1 here, square root of 3 here and 2 here.
The question asks for the length of DE; well, we know that DE is to DF as square root of
3 is to 1...
DF has a length of 10 and
the key equation looks like this:
Square root of 3 over 1 equals DE over 10.
Cross multiply and we have 10 times square root of 3 equals 1 times DE... or just, uh, DE...
So the answer is B.