The top of a gateway is an arc of a circle of radius 35 cm in a scale drawing…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
The top of a gateway is an arc of a circle of radius in a scale drawing. The arc makes an angle of at the centre. Find the length of the arc, and the perimeter of the sector that the arc and the two radii bound. Take .
Need a reminder? The key ideaShow
An arc that makes an angle at the centre has length . The perimeter of a sector is . In radians, .
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Given. , .
Step 1. The fraction. .
Step 2. The arc. .
Step 3. The perimeter. .
Answer: the arc is and the perimeter of the sector is .
Check. The arc is a fifth of the circumference, and the angle is a fifth of a full turn.
Discussion (0)
Log in to join the discussion.
Loading…