Area of figures

/* Calculate the Area of figures*/

function areaOfFigures(input) {
    //1. read input and parse numbers;
    let shape = input[0];
    let area = 0;
    //2. choose figure types & calculate area;
        if (shape == "square") {
        let side = Number(input[1]);
        area = Math.pow(side, 2);
    } else if (shape == "rectangle") {
        let sideA = Number(input[1]);
        let sideB = Number(input[2]);
        area = sideA * sideB;
    } else if (shape == "circle") {
        let side = Number(input[1]);
        area = Math.PI * (Math.pow(side, 2));
    } else if (shape == "triangle") {
        let sideА = Number(input[1]);
        let height = Number(input[2]);
        area = (sideА * height) / 2;
    }

    return area.toFixed(3);

}
console.log(areaOfFigures(["triangle", "4.5", "20"]));