Which picture shows 180° of a circle?
180∘ of a circle is half of a circle (that is half of 360∘=180∘) The above image is half of a circle. That is 180∘ of a circle.
Which picture shows 90∘ of a circle?
Draw a picture that shows where you could cut a cylinder so that cross-section is shaped like a circle.
A picture which display information as parts of a circle is called pie chart.