need help with a couple of question for trigo (1 Viewer)

[red802]

Find the exact length of a circle if
a) radius is 4cm and angle subtended is n(pie)

next question
find the area of the sector, correct to 2 decimal places, given
(a) radius is 1.5m and angle subtended is 0.43

show working out please

 

[Mountain.Dew]

Find the exact length of a circle if
a) radius is 4cm and angle subtended is n(pie)

next question
find the area of the sector, correct to 2 decimal places, given
(a) radius is 1.5m and angle subtended is 0.43

show working out please

for a) ...isnt the exact length of a circle the circumference? in that case, its simply just 16(pi) units squared

however, if ur talking about the length of SECTOR, then its 4 + 4 + 4(n(pi))

= 8 + 4npi

for next question:

area of sector (to my understanding) is = 1/2r^2(theta) = 1/2(16 * 0.43) = some number.

note that 0.43 is in radians

hope this helps, M.D.

if i got anything mathematically wrong, please correct me!

 

[Riviet]

Just a couple of things to clarify:

1) If the question asks for an exact value answer, don't give decimal approximations. This can mean leaving your answer in terms of pi or in surd form.

2) If given units, use them in your answer. If none are given, such as in finding areas under curves, then use units² or u². For the second question, use m², since those are the units you're given in the queston.