Could anyone help with this question please Watch
This question in a practice paper has me stumped, I think i've done it but wondered if someone could check my answer.
2.Convert this angle into radians.
90 degrees = pi/2
3. To find the length of the curved edge multiply the angle (in radians) by the radius of the sector.
4. Then add the length of the two straight sides, which are equal to the radius.
Answer is 214.25
let's divide that shape you assumed into two equal parts by a horizontal line and you will end up with a shape just like in the question.
divide this shape further into two equal parts by a verticle line and you will get that part of the shaded region. now you realise that this part is a 1/4th of the original shape you imagined.
for the perimeter you will need the two sides and the arc length. ..the two sides will be 60 because it was a square initially so the sides remain equal...now you need the arc length.
the arc made there is 1/4 of the original circumference of the whole circle we imagined that means that the length of that arc will be 1/4 * circumference of the circle. and you know circumference = pi*diameter and our diameter was 120 so the length of the arc will be 1/4 * pi*120 = 30pi.
so finally the perimeter is 30pi + 60 + 60 = 30pi + 120.
let me know if I helped