ACT Math 3.2 Trigonometry
ACT Math: Trigonometry Drill 3, Problem 2. What is the value for side DF on this triangle?
|Foreign Language||Arabic Subtitled|
|Geometry||Right Triangles and Trigonometry|
|Product Type||ACT Math|
|Trigonometry||Solving right triangles|
Trigonometric relations in right triangles
We know that the ratios of the sides in a 30-60-90 triangle are 1 to square root of 3 to 2...
...and we know that this line, DF, will be an index of 1... EF will be 2...
So we can make a simple ratio here where DF is to EF as 1 is to 2.
We are told that EF is 15... so 1 is to 2 as DF is to 15.
Now we just cross-multiply 15 times 1, like this... and set it equal to 2DF.
Then divide both sides by 2 and we have DF equals 7.5.