How do I find the area? Diagram included?

Question

anyone know?

i cant think of anything atm

http://i35.tinypic.com/2njzo7b.jpg

It's triangle 40m on all sides, and a circle with a radius of 30m

and im looking to find the area of the red region, how do i do that

please be detailed so it can help, thanks

Answer 1

the radius is 30 so you may easily find the triangle left-down angle point is at the circle center.

The whole circle's area is pi*(30m)^2 = 2827.35m^2

while the triangle's side length is 40,40,40. so we know all its angles are 60dgree.

Therefore the area is circle minus the area which the circle and triangle overlapped (like a piece of Pizza!). and that piece of Pizza takes 1/6 circle's area(for it's angle is 60dgree).

The answer is 2827.35*(5/6)=2356.12m^2

Answer 2

The missing sector of the circle is 60 degrees. So, the red sector is 300 degrees. Just calculate the area of the red sector, using the ratio of the angle to the 360 degrees of the entire circle: (300/360)(pi)(r^2)

(300/360)(900pi) = 750pi square meters

Answer 3

area of the red region = area of circle -  area of the sector

= pi*30*30   -  pi*30*30*(60/360)

= 750pi metre sqr

see what is sector of a circle and formula for its area.

http://www.mathwords.com/a/area_sector_c...