Because if it is linear it is a straight line so the slope must always be equal to eachother
For the sake of showing work I will replace the empty space with an x like so...

To find out what x is you must cross multiply (aka butterfly)
***Image of this step is attached below
9*x = 10*90
9x = 900
Next divide 9 to both sides to finish isolating x. Since 9 is being multiplied by x, division (the opposite of multiplication) will cancel 9 out (in this case it will make 9 one) from the left side and bring it over to the right side.
9x ÷ 9 = 900 ÷ 9
1x = 100
x = 100
To make these fractions equivalent the empty spot must be 100

Hope this helped!
~Just a girl in love with Shawn Mendes
Answer:
the third one is hard to see i think its 77 so the answer is 54.75
Step-by-step explanation:
Ok, so i got 144 cubic cubic meters by multiplying 6 by 6 by 4. Tell me if it's correct because i'm not the best at Math, but I checked and rechecked it. <span />
Answer: 24
Step-by-step explanation: 6 x 4=24