Observe the given figure.
Here, angle T and R are the inscribed angles.
And sum of inscribed angles is half of measure of intercepted arcs.
Since, the measure of intercepted arcs is 360 degrees.
Therefore, 

Hence, the sum of the two angles is 180 degrees.
Therefore, these are the supplementary angles.
Therefore, angle T and angle R are supplementary angles.
Hence, proved.
Answer:
B. 18
Step-by-step explanation:
Given:
There are two chord in the circle.
These chords are divided in two segments.
Segments of 1 chord is 21 and 6.
Segments of 2 chord is x and 7.
Now by using Intersecting Chord Theorem which states,
"When two chords intersect each other inside a circle, the products of their segments are equal."
Hence from above theorem we can say that;

Hence the Value of x is 18.
Answer:
C
Step-by-step explanation:
Sorry if I’m wrong but I think I’m right
X=25 in this equation. But if u divide by 12 it’s -25
The goal is to construct a triangle. If you choose A) you will only have two lines connecting, with an angle of 90°. If you choose B) you cannot have a triangle also with 2 lines only. Neither D). So choose C) construct an angle congruent to a given one-- connect the lines and produce a perfect triangle.