Sam is designing a fence post for his yard. he will need to construct a perpendicular line through the point above the line to make sure the fence post is perpendicular to the ground. which step should sam do first to ensure that the fence post model is perpendicular to the ground in the diagram? a. place the compass at the point off the ground, and swing an arc on either side of the point. b. place the compass at the point off the ground, and swing arcs above and below the ground. c. place the compass at the point off the ground, and swing an arc that intersects the ground in one place. d. place the compass at the point off the ground, and swing an arc that intersects the ground in two places.