Trouble visualizing distances from objects

hello! i recently made a black hole in gdevelop, so i thought the next best thing would be some planets! but i am having trouble visualizing the distance you need to be from the planet for its gravity to affect you, what i did in code for the distance, was the width of the planet + 100, and i thought i could simply scale the object i was using to visualize it by doing the same thing, but this seems to be very inaccurate, let me know if you want more details about my code or something else. thanks

the blue outline is the object i am visualizing the gravity distance with

you also need to multiply the positions, not just the dimensions

could you help me understand a little more? what do i need to change or add to planet.Width() + 100 exactly

scaling an object happens relative to a point. if that point is in the center of the object, scaling just alters its radius…if the point is elsewhere, the object is translated as well.