Question

You are standing on the beach looking out over the water. You see a sailboat off in the distance and want to try and figure out how far away it is. Being a sailboat aficionado, you know this particular boat has an 80-foot mast. You decide to use your 10-foot beach umbrella to calculate the distance to the boat. You lie down on the sand 20 feet away from your umbrella and are able to look out at the boat. The umbrella and the mast are now lined up. Determine how far away the boat is.

I need to get the response and the steps you followed to reach ..please guys help me really need your help :)