# Math Help - Trigonometry

1. ## Trigonometry

B is a right angle.DF is the dotted vertical line from D

2. Do you have any other angles besides C? It seems to me that the distance from D to A could be anything if angle B is not fixed.

3. i forgot to indicate. B is a right angle.

4. "C is 320°"

in the drawing C seems less than 180°

5. what are you trying to find? your sketch says "DF"

6. Originally Posted by helloying
i forgot to indicate. B is a right angle.
You don't forget.

7. C is not 320 degree. sorry if my scan is not clear. What i wrote is The bearing of D from C is 320 degree.The sentence continue to C...

And I am suppose to find the dist DF

8. Originally Posted by helloying
C is not 320 degree. sorry if my scan is not clear. What i wrote is The bearing of D from C is 320 degree.The sentence continue to C...

And I am suppose to find the dist DF

ok ... maybe my eyesight is worse than i thought

where is F?

9. Omg! I didn't indicate. I am so blur. It is the dotted vertical line.

10. if point F is at the bottom of the dashed line segment, then ...

$DF = 150 + 200\cos(40^{\circ})$

11. With B a right angle its do-able. Consider the little triangle made if you draw a horizontal line across the rhombus on the right from the intersection at angle C to the dotted line. You have have a right triangle and since you know C you know all if its angles, and you know its hypotenuse is 200, so you can solve for all its sides. Then you know the base length of the rhombus and the height. Then you know the base length of the big triangle on the left and its height, and use pythagorean theorem to solve for the hypotenuse.