Question

AB = 6 cm AC= 12 cm calculate length of CD give your answer to 3 significant figures

Answer 1

Explanation:

63

Answer 2

The length of CD to 3 significant figures is 12.7

What is the length of CD ?

Given that;

AB=6cm AC=12cm.

Using Pythagoras in triangle ABC

`(AC)^(2) =(AB)^(2)+(BC)^(2)`

`(12)^(2) =(6)^(2)+(BC)^(2)`

`144 - 36 = (BC)^(2)`

`(BC)^(2) =108`

`(BC)=√(108)`

We can then use Law of sine as;

`(a)/(sinA) =(b)/(sinB) =(c)/(sinC)`

`(CD)/(sin90) =( √(108) )/(sin55)`

`(CD)/(1) = (√(50) )/(sin55)`

`CD=12.6866`