First you need to know the definition of a complementary angle. That means that two angles add up to 90 degrees, or a right angle.
To find an angle complementary to a 78 degree angle, you need to subtract 78 from 90.
90 - 78 = 12
<em>only the last figure (i.e figure e) is shaded </em>
The shaded region is a triangle
Area of a triangle
= ½ × b × h
= ½ × 14 × 5
= ½ × 70
= 35yd²
Considering the unit circle, it is found that the sine is negative on the third and on the fourth quadrant.
<h3>What is the unit circle?</h3>
For an angle
the unit circle is a circle with radius 1 containing the following set of points:
.
Hence, from the above explanation, the sine is negative when y is negativem, which is on the third and on the fourth quadrant.
More can be learned about the unit circle at brainly.com/question/16852127
#SPJ1