Circumference: Calculating parts of the circle

Jacob cut a slice that was $\frac{1}{6}$ of a whole cake.

What is the circumference of the cake now given that its radius is 20 cm?

$33\frac{1}{3}\pi+40$ cm

Given the circle in the figure,

and above it there are two arches marked in blue.

The radius is equal to 5.

What is the sum of the lengths of the arcs?

$2.5\pi$ cm

Given the circle in the figure

Radius of the circle $5a+8$ cm

The sector marked in blue is displayed by an angle of size 24 degrees.

What is the circumference of the section marked in blue?

$10a+16+(\frac{2}{3}a+1\frac{1}{15})\pi$ cm

Look at the circle in the figure.

What is the perimeter of the segment highlighted in blue?

39.12 cm

The radius or the circle shown below is 4 cm.

What is the circumference of the shape marked in blue?

$\frac{5}{3}\pi+24$ cm

In the drawing, a rectangle and a circle whose center is the corner of the rectangle.

Given R=4

What is the length of the highlighted part in the drawing?

$\frac{32}{45}\pi$