Question

I got this question correct because I guessed,but can someone show how to get this answer

Answer 1

Hello from MrBillDoesMath!

Answer:

Choice C. (a = 8* sqrt(3) )

Discussion:

From plane trigonometry:

cos(30) = a/16

As cos(30) = sqrt(3)/2, this is equivalent to

sqrt(3)/2 = a/16.

Multiply both sides by 16 to get

( sqrt(3)/2 ) * 16 = a

or

a = 8* sqrt(3)

Thank you,

MrB

Answer 2

8 sqrt(3) =a

Explanation:

We know that sin 60 = opposite / hypotenuse

sin 60 = a/16

sqrt(3)/2 = a/16

Multiply both sides by 16

16 sqrt(3)/2 = a/16*16

8 sqrt(3) =a

I would memorize sin, cos, tan for 30 degrees, 45 degrees and 60 degrees