## ErinWeeks 2 years ago The area of a regular octagon is 35 cm2. What is the area of a regular octagon with sides five times as long? A. 625 cm2 B. 875 cm2 C. 175 cm2 D. 245 cm2

1. Hero

Do you have the formulas for Area of a Polygon already?

2. ErinWeeks

no i dont ! could you tell me the area

3. Hero

$A = \frac{Pa}{2}$

4. ErinWeeks

what is PA? what would i put there?

5. mathmate

Hint: Area of similar polygons are proportional to the square of the linear dimensions (such as a side). A polygon with a side 5 times as long has an area of 5^2=25 times the smaller polygon.

6. Hero

^What he said

7. ErinWeeks

so it would be B , 875 ?

8. mathmate

Sounds good to me. :)

9. Hero

I was just about to show her the long hard way of doing it.

10. Hero

Nice intercept @mathmate

11. ErinWeeks

thank you both !!

12. mathmate

Sorry @Hero for butting in. I think the question was on the proportionality of figures.

13. mathmate

yw! :)

14. Hero

It was on Area of a Regular Polygon as well

15. mathmate

It would definitely been beneficial to learn how to calculate the apothem and the length of the side given the area and number of sides. It would be a little long though.

16. Hero

Yes, I know. I just said that it was the long way. Good job on saving time.

17. mathmate

Sorry pal for this time. Hope that won't happen again! :)

18. Hero

Okay bro