Surface Calculator

SurfaceCalculator.php

<?php

/**
 * Class SurfaceCalculator
 *
 * This class provides methods to calculate the area of various shapes
 * like polygons, triangles, rectangles, circles, trapezoids, and ellipses.
 */
class SurfaceCalculator {
    /**
     * Calculate the area of a polygon using the Shoelace formula.
     *
     * @param array $points An array of associative arrays containing x and y coordinates.
     * @return float The area of the polygon.
     * @throws InvalidArgumentException If the number of points is less than 3.
     */
    public static function calculatePolygonArea($points) {
        $num_points = count($points);
        if ($num_points < 3) {
            throw new InvalidArgumentException("A polygon must have at least 3 points.");
        }

        $area = 0;

        for ($i = 0; $i < $num_points; $i++) {
            $next_index = ($i + 1) % $num_points;
            $area += ($points[$i]['x'] * $points[$next_index]['y']) - ($points[$next_index]['x'] * $points[$i]['y']);
        }

        return abs($area) / 2;
    }

    /**
     * Calculate the area of a triangle given its base and height.
     *
     * @param float $base The length of the triangle's base.
     * @param float $height The length of the triangle's height.
     * @return float The area of the triangle.
     */
    public static function calculateTriangleArea($base, $height) {
        return 0.5 * $base * $height;
    }

    /**
     * Calculate the area of a triangle using Heron's formula.
     *
     * @param float $a The length of the first side of the triangle.
     * @param float $b The length of the second side of the triangle.
     * @param float $c The length of the third side of the triangle.
     * @return float The area of the triangle.
     */
    public static function calculateHeronTriangleArea($a, $b, $c) {
        $s = ($a + $b + $c) / 2;
        return sqrt($s * ($s - $a) * ($s - $b) * ($s - $c));
    }

    /**
     * Calculate the area of a rectangle given its length and width.
     *
     * @param float $length The length of the rectangle.
     * @param float $width The width of the rectangle.
     * @return float The area of the rectangle.
     */
    public static function calculateRectangleArea($length, $width) {
        return $length * $width;
    }

    /**
     * Calculate the area of a circle given its radius.
     *
     * @param float $radius The radius of the circle.
     * @return float The area of the circle.
     */
    public static function calculateCircleArea($radius) {
        return pi() * pow($radius, 2);
    }


    /**
     * Calculate the area of a trapezoid given the lengths of its parallel sides and the height.
     *
     * @param float $a The length of the first parallel side of the trapezoid.
     * @param float $b The length of the second parallel side of the trapezoid.
     * @param float $height The height between the parallel sides of the trapezoid.
     * @return float The area of the trapezoid.
     */
    public static function calculateTrapezoidArea($a, $b, $height) {
        return 0.5 * ($a + $b) * $height;
    }

    /**
     * Calculate the area of an ellipse given the lengths of its semi-major and semi-minor axes.
     *
     * @param float $a The length of the semi-major axis of the ellipse.
     * @param float $b The length of the semi-minor axis of the ellipse.
     * @return float The area of the ellipse.
     */
    public static function calculateEllipseArea($a, $b) {
        return pi() * $a * $b;
    }
}