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Module DEMO-32-89DEMO-C-32

Area of a Circle

DEMO-C-32 • Programming in C

Browser-only practice

Problem Statement

Write a program that calculates the area of a circle given its radius r.

Use the formula: Area = PI * pow(r, 2). Use 3.14159 for PI.

Target difficulty: Easy

Constraints

r >= 0

Input Format

A single floating-point number r.

Output Format

The area formatted to 2 decimal places.

Sample Testcases

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Sample #1
Public sample
Input
1.0
Output
3.14
Explanation
PI * 1.0^2 = 3.14159 * 1.0 = 3.14
Sample #2
Public sample
Input
5.0
Output
78.54
Explanation
PI * 5.0^2 = 3.14159 * 25.0 = 78.54
Sample #3
Public sample
Input
0.0
Output
0.00
Explanation
PI * 0.0^2 = 3.14159 * 0.0 = 0.00
Sample #4
Public sample
Input
100.0
Output
31415.90
Explanation
PI * 100.0^2 = 3.14159 * 10000.0 = 31415.90

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