You would do 3/4 of 20.
20 / 4 = 15
15 pens have black ink.
y = 5x, so 5 is the constant of proportionality
Answer:
A. Playfair's axiom.
Step-by-step explanation:
In a plane, given a line and a point not on it, at most, one line parallel to the given line can be drawn through the point.
- this implies Euclid's fifth postulate.

Answer:
1.01 × 10⁴ - scientific notation
10,100 - decimal notation
Fifty two thousand fifty two is equal to 52,052.