Question

60)
A decagon has how many diagonals?

a) 10
b) 15
c) 25
d) 35

Answer 1

Use this formula to get the number of diagonals, where x is the number of sides:

\(\Large \color{purple}{\rightarrow {x(x - 3) \over 2} }\)

Answer 2

If x = 3, then:

\(\Large \color{purple}{\rightarrow {10(10 - 3) \over 2} }\)

\(\Large \color{purple}{\rightarrow {10(7) \over 2} }\)

\(\Large \color{purple}{\rightarrow {70 \over 2} }\)

\(\Large \color{purple}{\rightarrow 35 }\)

Answer 3

so the answer is 35?

Answer 4

Yes.

Answer 5

thanks

Answer 6

np!