Proportional relationships and the constant of proportionality

Use this for “If 3/20 = n/300, what is n?” and “450 g of oats makes 12 bars; how much for 20 bars?”

Use this for “1/2 cup of sugar for every 3/4 cup of flour: how much sugar for 1 cup of flour?”

Use this for “Does the table show a proportional relationship?” or “Is y = 2x + 1 proportional?”