Error: cannot implicitly convert type "double" to "int"

Program.cs(35,39): error CS0266: Cannot implicitly convert type `double' to `int'. An explicit conversion exists (are you missing a cast?) 

using System;

namespace Treehouse.PracticeSession
{
    class Program
    {
        public static void Main()
        {
            // TODO Declare a boolean variable named "keepGoing"
            // and assign it a value of "true". Use this variable to 
            // know when to exit the while loop.
            bool keepGoing = true;

            // TODO Define a while loop.
            // Keep looping as long as the variable "keepGoing" has a value of "true".
            while (keepGoing)
            {
                // TODO Prompt the user with the text "Enter a number:"
                Console.Write("Enter a number or type \"quit\" to exit: ");
                // and assign their value to an "entry" string variable.
                string entry = System.Console.ReadLine();
                // TODO If the user entered the text "quit"...
                if (entry == "quit")
                    // TODO Exit the program.
                {
                    keepGoing = false;
                }
                // TODO Else the user didn't enter the text "quit"...
                else 
                {
                    // TODO Parse the user's entry to an integer
                    int number = int.Parse(entry);
                    // TODO Square the user's provided number 
                    // (i.e. multiply the number by itself).
                    int square = Math.Pow(number, 2); // This line caused the error.
                    // TODO Output the result.
                    // Example: "The square of 2 is 4." or 
                    // "2 multiplied by itself is equal to 4."
                    Console.WriteLine("The square of " + number + " is " + square + ".");
                }
            }
            // TODO Output the text "Goodbye!" after exiting the loop.
            keepGoing = false;
            Console.WriteLine("Goodbye!");
        }
    }
}