Hello,
very simple they intercept supplementary arcs. (making a sum of 360°/2 for inscribed angles )
Answer:



Step-by-step explanation:
Given
See attachment for triangle
Required
Find
and
of angle Y
For angle Y:


The
of an angle is calculated as:

So:

The
of an angle is calculated as:

So:

The
of an angle is calculated as:

So:

True because tan(20)=2.1 and cot(20)=is o.44
Answer:
773 and 869 and 703 on any day