Here's one way to do it:

$pi = 3.141592654; $result = 2 * $pi * 12.5; print "radius 12.5 is circumference $result\n";

First, we give a constant value () to the scalar variable

`$pi`. Next, we compute the circumference using this value of`$pi`in an expression. Finally, we print the result using a string containing a reference to the result.Here's one way to do it:

print "What is the radius: "; chomp($radius = <STDIN>); $pi = 3.141592654; $result = 2 * $pi * $radius; print "radius $radius is circumference $result\n";

This is similar to the previous exercise, but here we've asked the person running the program for a value, using a

`print`statement for a prompt, and then the`<STDIN>`operator to read a line from the terminal.If we had left off the

`chomp`, we'd get a newline in the middle of the displayed string at the end. It's important to get that newline off the string as soon as we can.Here's one way to do it:

print "First number: "; chomp($a = <STDIN>); print "Second number: "; chomp($b = <STDIN>); $c = $a * $b; print "Answer is $c.\n";

The first line does three things: prompts you with a message, reads a line from standard input, and then gets rid of the inevitable newline at the end of the string. Note that since we are using the value of

`$a`strictly as a number, we can omit the`chomp`here, because`45\n`is 45 when used numerically. However, such careless programming would ...

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