If 3/4 cup plain yogurt equals to 90 calories, how many calories does 1/2 cup equal to

There are three 1/4 cups in 3/4, so divide 90 by 3 to find how many calories are in 1/4 cup

90 / 3 = 30 calories per 1/4 cup.

1/2 cup contains two 1/4 cups (1/4 + 1/4 = 1/2)

Multiply 30 calories per 1/4 cup by 2:

30 * 2 = 60

1/2 cup of yogurt contains 60 calories.