Answer:
Step-by-step explanation:
divide 20 by four
20/4=5/1
now 10 and 15 can both be divided by 5 since 5 is the greatest common factor
10/15=2/3
Answer:

Step-by-step explanation:
We can apply Pythagoras' Theorem.

Answer:
5 and negative 5
Step-by-step explanation:
The absolute value is the distance from 0 five and negative 5 are both the same distance from zero
Step-by-step explanation:
3/4:2/5=3/4×5/2=15/8
3/8 ÷ 2/12=3/8 ×12/2=36/16=9/4