float area;
float r = 2;
float pi = 3.1428;
int delayT = 650;
void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
}
void loop() {
  // put your main code here, to run repeatedly:
  Serial.print(" Circle having radius ");
  Serial.print(r);
  Serial.print(" Has an area of ");
  // r = r + .5; here it will give value of 19.64
  area = pi * r * r;
  Serial.print(area);
  delay(delayT);
  // r = r + .5;  Here if i use it it will give me the value of 12.57 then it will give us the value of 19.64 for the value of 2.50
}