find the area of a sector.

Question

find the area of a  sector.

highschoolmom2010 · Answer

attachment

highschoolmom2010 · Answer

|dw:1385147882662:dw|

highschoolmom2010 · Answer

thats as far as i understand

amistre64 · Answer

what is the area of a circle that has a diameter of 9.1?

highschoolmom2010 · Answer

how do i find that

amistre64 · Answer

how do you find the area of a circle?  that is a formula that you need to memorize and know by now

highschoolmom2010 · Answer

$$A=\pi*r^2$$
$$A=\pi*9.1^2$$
$$A=\pi*\frac{ 9.1 }{ 2 }^2$$
$$A=4.55^2\pi$$
$$A=20.7\pi$$



am i on the right track

amistre64 · Answer

thats perfect so far yes

highschoolmom2010 · Answer

ok so where do i go next with this

amistre64 · Answer

there are 2 ways we can approach this ... exact and approximate

approximate is to see that 170 is almost 180, its almost half a circle

the area we are looking for will be a little less then half the area of the full circle

highschoolmom2010 · Answer

i believe my teacher wants exact

amistre64 · Answer

exactly, we know that we have 170 out of 360, for a proportion of 170/360 of the full area

amistre64 · Answer

so we want to know that area of about 47% of the full circle

amistre64 · Answer

think of it this way:

we have 20.7pi amount of pie, and we cut it into 360 slices:  20.7pi/360

how mush is  170 of those slices?  170 * 20.7pi/360

highschoolmom2010 · Answer

30.7090681888

amistre64 · Answer

|dw:1385144630777:dw|

yes, which is a little less than 20.7pi/2 :)