Please help with this question!

I got 40 pi but its not right?

I got 40 pi but its not right?

(Apologies for the terrible quality picture)

Draw in construction lines and you can see that the total length is equal to 8 lots of the radius (or 4 lots of the diameter) plus 4 lots of a quarter of the circumference of one circle (or just one circumference =2(pi)r))

So the total length is 4(10) + 2(pi)(5) = 40 + 10(pi) (which might be the correct answer)

Thanks but I still don't understand anything. Where do you start? I calculated 40 pi from using the diameter, but i don't understand how you got 10 pi

Start b drawing rough construction lines through the centre of each circle horizontally and vertically (in red on my picture). You will then see that the straight sections of the band are equal to the diameter of one of the circles, and we have four of these which is where the 40 comes from. We now look at the remaining section of the band which covers a quarter of the circumference of each of the 4 circles. We know the circumference of a circle =2(pi)r and we know that we are looking for 4 lots of 1/4 of the circumference which is just equal to the circumference of one circle = 2(pi)(5) = 10(pi)

(the radius is half the diameter which =10/2 =5)

Let me know If you're still stuck

Ohhhhh thanks! I didn't understand how the middle section was 10, but then i realised it was 2 of the radii. Also, I didn't split the question up and problem solve. Thats my weak point Thanks!

Start b drawing rough construction lines through the centre of each circle horizontally and vertically (in red on my picture). You will then see that the straight sections of the band are equal to the diameter of one of the circles, and we have four of these which is where the 40 comes from. We now look at the remaining section of the band which covers a quarter of the circumference of each of the 4 circles. We know the circumference of a circle =2(pi)r and we know that we are looking for 4 lots of 1/4 of the circumference which is just equal to the circumference of one circle = 2(pi)(5) = 10(pi)

(the radius is half the diameter which =10/2 =5)

Let me know If you're still stuck