Answer:
A. add 81; 
Step-by-step explanation:
The perfect square formula

Rewrite expression
as follows:

So, to form a perfect square,
is missed.
When we add
we will get

Answer:
20
Step-by-step explanation:
16 divided by 4/5 = 20 :)
Multiplying the number by 1,000
Answer:
45 degrees
Step-by-step explanation:
All triangles equal 180 degrees so your just add the two existing angles which gets you 135 then you do 180-135, therefore giving you 45