You can do anything you want. You can even use Javascript, Python, PHP or anything else as long as it also uses App Inventor and is made to celebrate Pi Day.

My little car always has Pi Day. Look at the license plate. But i can not enter that for the challenge because it doesn't use App Inventor............ yet.....

To be honest this is actually a calculator for the area of a circle WITHOUT using Pi, just using a value of r=1 returns an approximation of Pi. They built the pyramids with stuff like this.

This event is fired when the system has got the pi value from the GetPi block successfully.

Parameters: result = text

GetPi

Generates digits of pi according to the accuracy parameter. When the accuracy parameter increases, so does the number of digits and it will become closer to the real pi.

package com.gordonlu.pi;
import android.app.Activity;
import android.content.Context;
import com.google.appinventor.components.annotations.*;
import com.google.appinventor.components.common.ComponentCategory;
import com.google.appinventor.components.runtime.AndroidNonvisibleComponent;
import com.google.appinventor.components.runtime.ComponentContainer;
import com.google.appinventor.components.runtime.EventDispatcher;
import java.math.*;
import java.lang.*;
import java.lang.StringBuffer;
import java.util.Arrays;
@DesignerComponent(
version = 1,
description = "A non-visible extension that is used to celebrate Pi day by calculating digits of pi.",
category = ComponentCategory.EXTENSION,
nonVisible = true,
iconName = "https://docs.google.com/drawings/d/e/2PACX-1vQCI87PHLBF0jb8QWyYmIRQSjjNW3EFXf-qpsWCvBYkUQ9vEgPAB8SpxcMpblxNpbIYrjCjLrRLIU2c/pub?w=16&h=16")
@SimpleObject(external = true)
//Libraries
@UsesLibraries(libraries = "")
//Permissions
@UsesPermissions(permissionNames = "")
public class Pi extends AndroidNonvisibleComponent {
//Activity and Context
private Context context;
private Activity activity;
public static BigDecimal pi = BigDecimal.ZERO;
public static BigDecimal denom1 = BigDecimal.ONE;
public static BigDecimal denom2 = BigDecimal.ONE;
public static BigDecimal term1 = BigDecimal.ZERO;
public static BigDecimal term2 = BigDecimal.ZERO;
public Pi(ComponentContainer container){
super(container.$form());
this.activity = container.$context();
this.context = container.$context();
}
@SimpleFunction(description = "Generates digits of pi according to the accuracy parameter. When the accuracy parameter increases, " +
"so does the number of digits and it will become closer to the real pi.")
public void GetPi(int accuracy){
String p = pi_digits(accuracy);
GotPi(p);
}
public static String pi_digits(int digits){
StringBuffer pi = new StringBuffer();
int[] arr = new int[digits + 1];
int carry = 0;
for (int i = 0; i <= digits; ++i)
arr[i] = ARRINIT;
for (int i = digits; i > 0; i-= 14) {
int sum = 0;
for (int j = i; j > 0; --j) {
sum = sum * j + SCALE * arr[j];
arr[j] = sum % (j * 2 - 1);
sum /= j * 2 - 1;
}
pi.append(String.format("%04d", carry + sum / SCALE));
carry = sum % SCALE;
}
return pi.toString();
}
private static final int SCALE = 10000;
private static final int ARRINIT = 2000;
@SimpleEvent(description = "This event is fired when the system has got the pi value from the GetPi block successfully.")
public void GotPi(String result) {
EventDispatcher.dispatchEvent(this, "GotPi", result);
}
}

14th March for the countries following the MM-DD format and 22nd July for the countries following the DD-MM format. (31st April would have worked just fine, but then we don't have it on our calendar )

You can make him a 22/7 themed pi cake on his birthday

Ah an interesting case

As a student I switch my choice depending on the situation. 3.14 for 10 and its multiples and 22/7 for 7 and its multiples. Saves you a lot of time during exams.

pi never equals 22/7. As 22/7 is a rational number but pi is irrational(non-terminating value). Since, 22/7 is easy to use, our school books and teachers uses this value.

pi is actually division of Circumference of Circle (2πr) by diameter (2r).