Question

What is the missing side

Answer 1

`\text{Use the Pythagorean theorem}\\\\leg^2+leg^2=hypotenuse^2\\\\x^2+\left((4)/(7)\right)^2=\left((5)/(7)\right)^2\\\\x^2+(16)/(49)=(25)/(49)\ \ \ \ \ |-(16)/(49)\\\\x^2=(9)/(49)\to x=\sqrt(9)/(49)}\\\\x=(\sqrt9)/(√(49))\\\\x=(3)/(7)`

Answer 2

The Pythagorean theorem applies to the sides of this right triangle.

... x² + (4/7)² = (5/7)²

... x² = 25/49 -16/49

... x = √(9/49)

... x = 3/7

The unknown side has length 3/7.

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You might recognize that this is a 3-4-5 right triangle with a scale factor of 1/7.