Figures

function solve([type, side1, side2]){
    let a = Number(side1);
    let b = Number(side2);

    if(type == "square"){
        console.log((a * a).toFixed(3));
    }else if(type == "rectangle"){
        console.log((a * b).toFixed(3));
    }else if(type == "circle"){
        console.log((a * a * Math.PI).toFixed(3));
    }else if(type == "triangle"){
        console.log(((a * b) / 2 ).toFixed(3));
    }
}