In triangle ​ABC, AB= 21.1 ​, AC=12.3​, and BC=22.8 . What is measure of angle ​A?

How do you write something in scientific notation?

Set up and solve a proportion for the following application problem. if 55 pounds of grass seed cover 404 square feet, how many pounds are needed for 7272 square feet?

The architect's side view drawing of a saltbox-style house shows a post that supports the roof ridge. the support post is 8 ft tall. the distance from the front of the house to the support post is less than the distance from the post to the back of the house. how far from the front of the house is the support post positioned?