ACT Preparation / Unit 7 ACT 0622 short lesson, about 20 seconds
Proportions
Captions available
The idea
A proportion states that two ratios are equal. To solve one, cross-multiply: if a/b = c/d, then ad = bc.
In practice
x/12 = 5/8 gives 8x = 60, so x = 7.5.
Where people slip
Put matching units in matching positions: miles over hours on both sides, never miles over hours equal to hours over miles.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
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