Well they have to be perpendicual because they cross and parallel means that they are like lines on lines paper, they do not cross, they just keep going. Hope this helps :)
Answer: 30/40, 25/40, 4/40
Step-by-step explanation: Using the Least Common Denominator, I looked at each multiple of each number to determine 40 as the least common denominator, and since we did 4 x 10 to get 40 in the first one, we do 3 x 10 in the first one as well making it 30/40. The second one we did 8 x 5 to get 40, making the numerator (top number) the product of 5 x 5 which is 25 making it 25/40. For the last one, I used 10 x 4 to get 40 meaning I would have to do 1 x 4 to get the numerator (top number) making it 4/40
Answer:
You can subtract directly. $10 - $8.58. You will get the change amout.