I got this question wrong. So the 50% is not right. Please help.

Refer to interactive solution 17.45 to review a method by which this problem can be solved. the fundamental frequencies of two air columns are the same. column a is open at both ends, while column b is open at only one end. the length of column a is 0.504 m. what is the length of column b?

Nine more than four times a number is the same as one less than twice the number. find the number?

The area of a circle is equal to 1 dm². find the radius of the circle.