Answer:
Ok, the solution to the first one. See below.
Step-by-step explanation:

See attachment below.
Best Regards!
It's False; an octagon has 8 vertices. When you remove the starting vertex and the two adjacent vertices we're left with 5 possible diagonals
Area = base * altitude = 2 * 2.9 = 5.8 cm^2
Answer:
- A
Step-by-step explanation: