21 - 16.75 is 4.25. Do the problem on a calculator and you'll get it.
Don’t open the link the other person put in, it a virus
Answer:
it is 20.5
Step-by-step explanation:
you need to add all of the numbers together
For a regular polygon with n sides, interior angle
= [(n-2) × 180°]/n
So, interior angle of this regular heptagon shape
= [(7 - 2) × 180°]/7
= (5 × 180°)/7
= 900°/7
= (900/7)°
= 128.571° [approximately]
