How many edges does a triangular pyramid have

What is the difference between regular convex and concave polygons

The sum of the speeds of two trains is 720.2 mph. if the speed of the first train is 7.8 mph faster than the second train, find the speeds of each.

Tom and lilly rented a house for $12,000 last year. at the start of the year they bought the house they had been renting directly from the owner for $250,000. they believe they could rent it for $12,000 this year, but stay in the house. how much does tom and lilly’s decision to buy the house change gdp? a. it reduces gdp by $12,000 b. it does not change gdp c. it raises gdp by $238,000 d. it raises gdp by $250,000