float radius;
String msg = "What is the radius of your circle?";
float area;
String msg2 = "Your circle has an area of: ";
float pi = 3.14;
int dur = 500;

void setup() {
  // put your setup code here, to run once:
Serial.begin(9600);

}

void loop() {
  Serial.println(msg);
  while(Serial.available() == 0){

  }

  radius = Serial.parseFloat();
  area = pi * radius;

  Serial.println(msg2 + area);
  
  delay(500);


}