Answer:
We know that:
Sin(a + b) = sin(a)*cos(b) + sin(b)*cos(a)
Then if we use this property in our expression:
sin(a-30)-sin(a+30)
We get:
sin(a)*cos(-30°) + sin(-30°)*cos(a) - sin(a)*cos(30°) - sin(30°)*cos(a)
Now remember that:
sin(-x) = -sin(x)
and
cos(-x) = cos(x)
Then we can rewrite our expression as:
sin(a)*cos(30°) - sin(30°)*cos(a) - sin(a)*cos(30°) - sin(30°)*cos(a)
= -2*sin(30°)*cos(a)
and sin(30°) = 0.5
Then:
-2*sin(30°)*cos(a) = -2*0.5*cos(a) = -cos(a)
So we get:
sin(a-30)-sin(a+30)= - cos(a)
Answer:D)50
Step-by-step explanation:
12 ft I had the question the other day on online school :)
Sum of interior angle of a triangle is 180 degrees.
2x + 4x + 9x = 180
15x = 180
x = 180/15 = 12
2x = 2 x 12 = 24
4x = 4 x 12 = 48
9x = 9 x 12 = 108
the measures of the angles are : 24 degrees, 48 degrees ,108 degrees