How do you simplify to tell whether the ratios #1/2, 3/6# form a proportion?

Related questions

• What is the difference between proportions and ratios?
• What is the difference between ratios and rates?
• What are cross products?
• How do you write "12 meters to 4 floors" as a rate?
• How do you write and simplify "150 boys to 175 girls" as a ratio?
• How do you solve #\frac{6}{19} = \frac{x}{11}#?
• How do you solve #\frac{n+1}{11} = -2#?
• How do you solve #\frac{0.1}{1.01} = \frac{1.9}{x}#?
• How do you use proportions to solve how much money the restaurant made if it serves 250 people...
• How do you solve #x/4-7=13#?