Answer:
a) x=
10°
50°
130°
10°
50°
130°
170°
250°
290°
b) x=
90°
210°
330°
Step-by-step explanation:
2 sin (3x) = 1
a) look at the graph, y=1 when x is near:
10°, 50°, 130°, etc
in the equation: 2 sin (3x) = 1 ⇒ sin (3x) = 0.5 ⇒ 3x = 30° (and others) ⇒ x = 10° (and others). So the values given in solution (10°, 50°, 130°, etc) are true
b) is evident
The y-intercept is the point where the line crosses the Y-axis. And the X-intercept is where a line crosses the X-axis
The surface area of a sphere is

where r is the radius;
The circumference is

so that

using this value we can evaluate the surface area of 1 ball as:

For 100 ball you get:
answer B. 108°
because 30% of 360 = 108°