Answer:
Step-by-step explanation:
We can prove that a tangent will always be perpendicular to the radius touching it. So, the other angle in the diagram is 
.
Because all the angles of a triangle sum to 
, we have that 
.
We combine like terms on the left side to get 
.
We subtract 
on both sides to get 
.
So, 
and we're done!
Step-by-step explanation:
1. ΔABC=ΔCDE: a) according to the condition BC=CD and AC=CE; b) m∠(BCA)=m∠(DCE).
2. if ΔABC=ΔCDE, then m∠(BAC)=m∠(DEC) and m∠(ABC)=m∠(CDE).
3. if m∠(BAC)=m∠(DEC), then AB || DE (or if m∠(ABC)=m∠(CDE), then AB || DE).
SAS because you have 2 known side lengths and one angle!
Unit of measurement in a formula suggests a definite magnitude of a certain quantity. For instance, there are basic unit of measurement for the 7 basic quantities: These are
1. seconds (s) for time
2. meter (m) for length
3. candela (cd) for luminous intensity
4. Ampere (A) for electric current
5. Kelvin (K) for Temperature
6. Kilogram (kg) for mass
7. mole (mol) for amount of substance
These units of measure should be homogenous in a formula for easy interpretation. Other derived quantities (e.g volume) also have their corresponding units as well as those quantities which are not based on the metric systems (e.g Celsius, pounds, etc)
