ACT Preparation / Unit 13 ACT 1225 short lesson, about 20 seconds
The 45-45-90 Triangle
Captions available
The idea
In a 45-45-90 triangle, the legs are equal and the hypotenuse is a leg times √2: the sides are in the ratio 1 : 1 : √2.
In practice
Legs of 7 give a hypotenuse of 7√2. A square with side 5 has a diagonal of 5√2.
Where people slip
From the hypotenuse, divide by √2 to get a leg: 10 becomes 10/√2 = 5√2.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
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