WALKALONE

function $_collision(a, b) {
    var c = a.x - b.x,
        d = a.y - b.y,
        e = a.r + b.r;
    return c * c + d * d <= e * e
}
 
$_collision({
    x: 150,
    y: 200,
    r: 100
}, {
    x: 100,
    y: 150,
    r: 200
}); // true