help?!?!? ill fan and give a medal

Question

ilovebmth1234 · Answer

in the figure, if CD=15, then BC =?

ilovebmth1234 · Answer

A)6.6

B)11

C)21.6 

D)34.7

visarika23 · Answer

Ok now this q will require trigonometry....especially tan function

ilovebmth1234 · Answer

alright, i never really understood that

visarika23 · Answer

U must be knowing that in a right angle triangle perpendicular /base=tan(theta)
In this q AB/BD=tan70
AB/BC=tan40
Dividing these two u'll get BC/BD=tan70/tan40
Now u have to use calculator to calculate the value of tan70 and tan40

visarika23 · Answer

Now BC=BD+DC
And DC is given 15
So  
(BD+15)/BD =3.27
Mow u can solve for BD and u'll get d ans 6.6

ilovebmth1234 · Answer

xD thanks ill keep this method in mind <3

visarika23 · Answer

Ur wlcm☺

mrnood · Answer

@ilovebmth1234 
you have fallen into the trap of taking someone else's answer without understanding it

6.6. is not the correct answer

visarika23 · Answer

Sorry *answill be 21.6

visarika23 · Answer

U have to find BC=BD+CD

ilovebmth1234 · Answer

ohh its alright :3

mrnood · Answer

@ilovebmth1234 

Bear in mind that MANY answers given here are incorrect

ilovebmth1234 · Answer

?

ilovebmth1234 · Answer

21.6 was right