Substitution.
Here is an example.
Let x be equal to 3 and y equal to 3.

From this we can conclude that the values of both x and y are equal to three therefore x and y have the same value and are equal.

Here in your case we have:

Hope this helps.
r3t40
I think the answer should be 6,I just added the two fractions
Answer:
c: plane ptm
Step-by-step explanation:
Given:
In the circle,
and
.
To find:
The following measures:
(a) 
(b) 
Solution:
According to the central angle theorem, the central angle is always twice of the subtended angle intercepted on the same same arc.




In a cyclic quadrilateral, the opposite angles are supplementary angles.
UVWX is a cyclic quadrilateral. So,
[Opposite angles of a cyclic quadrilateral]
Now,
[Opposite angles of a cyclic quadrilateral]
Therefore,
and
.
Answer:
(Look at image)
Step-by-step explanation:
(Also look at image)