Insert parentheses to make each sentence true me with d. asap

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?

Consider that lines b and c are parallel. what is the value of x? what is the measure of the smaller angle?

The radius of the earth is two times the radius of the moon. what fraction of the volume of the earth is the volume of the moon?