4(x-2/3) = -18
4x - 8/3 = -18
4x = -54/3 + 8/3
4x = -46/3
x = -46/3 * 1/4
x = -46/12
x = -23/2
2x = -23/2 * 2
2x = -46/2
2x = -23
Answer = d
using the 30 - 60 - 90 triangle theorem
side across from the angle
across from angle 30 is x
across from angle 60 is x rad. 3
across from 90 is 2x
BC is across from angle 60
so BC is the x rad 3
set the given measurement equal to it
x sqrt 3 = 5
÷ sqrt 3 ÷ sqrt 3
x = (5/ sqrt 3)
multiply top and bottom by the radical to get rid of the radical in the bottom
x = (5/ sqrt 3) × (sqrt 3/sqrt 3)
x = 5 sqrt 3/ 3
since side BC is x
BC = 5 sqrt 3/ 3
* Drawing the triangle diagram would help*
39 degrees is the measure of the 3rd. Hope I helped. :) Please click thanks. :)