# NRICH PROBLEM SOLVING ANGLES

Days and Dates Investigate how you can work out what day of the week your birthday will be on next year, and the year after What shapes should Elly cut out to make a witch’s hat? A village has a pub, church and school. An introduction to variables in a familiar setting. Weekly Problem 13 – The diagram shows three squares drawn on the sides of a triangle. Why does this fold create an angle of sixty degrees?

Pythagoras on a Sphere Age 16 to 18 Challenge Level: What is the side length of the original triangle? Polygon Rings Age 11 to 14 Challenge Level: Who is the best? Can you work out their angles? Can you find triangles on a 9-point circle? How high is the top of the slide?

Watch the flower as you change the radii in this circle packing. Weekly Problem 35 – Two equilateral triangles have been drawn on two adjacent sides of a square.

Can you work out the area of a square drawn on a diagonal? Use your mouse to move the red and green parts of this disc. The green and red angles are opposite sopving. Lost Age 11 to 14 Challenge Level: Join the midpoints of a quadrilateral to get a new quadrilateral. Examples of the sorts of triangles yielded on a twelve-point circle can be seen in figure 4. Can you find the area of the yellow square? Weekly Problem 37 – Which of the statements about diagonals of polygons is false?

MGT503 FINAL TERM PAPER 2014

This task looks at the different turns involved in different Olympic sports as a way of exploring the mathematics of turns and angles. Shogi Shapes Age 11 to 14 Challenge Level: Why does this fold create an angle of sixty degrees? Weekly Problem 27 – Ten stones form an arch.

Well, initially, pupils could be invited to draw, by joining points on the six-point circle, different triangles and then encouraged to measure their angles.

Polygon Rings Age 11 to 14 Challenge Level: What if the triangle is on the surface of a sphere?

Making Sixty Age 14 to 16 Challenge Level: Admittedly she was following the scheme of work specified by her head of department, but it saddened me to see so many children doing something which they could clearly already do.

Weekly Problem 15 – How many of the five properties can a heptagon have? Geometry problems for primary learners to work on with others.

## Estimating Angles

Investigate how this is possible. Weekly Problem 19 – In the figure, what is the value of x?