Hypotenuse of a 3-4 Right Triangle
A right triangle with legs 3 and 4 has hypotenuse 5.
Problem
Answer
Step-by-step solution
Step 1: Square the legs
3² = 9 and 4² = 16.
Step 2: Add
9 + 16 = 25.
Step 3: Square root
c = √25 = 5.
Why this works
The Pythagorean theorem relates the two legs to the side opposite the right angle. 3-4-5 is a primitive Pythagorean triple; multiples such as 6-8-10 follow the same ratio.
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Frequently asked questions
Can I use this if the triangle is not right?
No. Without a right angle, use the law of cosines instead.