Checkpoint: the circle lessons

A bangle's way round divided by its way across is about 3.14. What does a tank give?

• More, since the tank has a longer rim
• Less, since the way across is a bigger number
• About the same, since both grow together

22/7 is close to π. Which statement is exactly right?

• π is 22/7, rounded to two places
• 22/7 is π, written as a fraction
• 22/7 is a fraction and π is not

22/7, 3.1416 and 355/113 each miss π. Which miss is smallest?

• 22/7, since it is the best known of the three
• 355/113, since it misses by about 0.00000027
• 3.1416, since it is the neatest decimal of the three

A circle of radius 7 has a way round of 44. How long is the arc for 90°?

• 44 units, since the arc is part of the rim
• 11 units, since 90° is 1/4 of the turn
• 154 units, since that is the area inside

Eight wedges are laid into a strip. What can we honestly say?

• The edges still curve, and the area matches the disc's
• The strip is now a true rectangle, with straight edges
• The strip's area is smaller than the disc's, by the bumps