Skip to main content
### Number and algebra

### Geometry and measure

### Probability and statistics

### Working mathematically

### For younger learners

### Advanced mathematics

# Take the Right Angle

## Take the Right Angle

**Why do this problem?**

### Key questions

### Possible extension

### Possible support

Or search by topic

Age 7 to 11

Challenge Level

- Problem
- Getting Started
- Student Solutions
- Teachers' Resources

How many times in twelve hours do the hands of a clock form a right angle?

What are these times to the nearest minute?

This problem is one which could be done as an introduction when extending or revising work on time and clocks. It will encourage the use of digital times.

At what time is the first right angle after 12 o'clock?

Why is it not just 15 minutes later?

Can you write down these times using digital notation

Why is the number of times not divisible by 4?

Learners could find out the times for 24 hours and record using 24 hour digital notation.

Using a geared clock would be helpful. (Some 'play' clocks allow you to move the minute and hour hands separately, which can lead to the hands being placed in an impossible way!)