(a) Complementary angles
(b) Vertical angles
(c) Supplementary angles
<u>Explanation:</u>
Complementary angles are those two angles whose sum is 90 degrees.
Supplementary angles are those two angles whose sum is 180 degrees.
Vertical angles are the angles opposite each other when two lines cross.
(a)
Angles 1 and 5 are complementary angles
(b)
Angles 3 and 5 are vertical angles
(c)
Angles 3 and 4 are supplementary angles
The tangent line is perpendicular to the radius from the center of the circle to the point of tangency.
ΔDCE is similar to ΔDBA
DC/DB=DE/DA
15/50=DE/40
DE=12
