Angles - points, lines and parallel lines

There are 81 NRICH Mathematical resources connected to Angles - points, lines and parallel lines
Outside the Nonagon
problem

Outside the nonagon

Age
11 to 14
Challenge level
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Weekly Problem 44 - 2010
Extend two of the sides of a nonagon to form an angle. How large is this acute angle?
Right Angle Challenge
problem

Right angle challenge

Age
5 to 7
Challenge level
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How many right angles can you make using two sticks?
Arrowhead
problem

Arrowhead

Age
14 to 16
Challenge level
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The points P, Q, R and S are the midpoints of the edges of a non-convex quadrilateral.What do you notice about the quadrilateral PQRS and its area?
Sweeping Hands
problem

Sweeping hands

Age
7 to 11
Challenge level
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Use your knowledge of angles to work out how many degrees the hour and minute hands of a clock travel through in different amounts of time.
Dotty Circle
problem

Dotty circle

Age
7 to 11
Challenge level
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Watch this film carefully. Can you find a general rule for explaining when the dot will be this same distance from the horizontal axis?
On Time
problem

On time

Age
11 to 14
Challenge level
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On a clock the three hands - the second, minute and hour hands - are on the same axis. How often in a 24 hour day will the second hand be parallel to either of the two other hands?
Angular Reflection
problem

Angular reflection

Age
11 to 14
Challenge level
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Weekly Problem 28 - 2013
Two lines meet at a point. Another line through this point is reflected in both of these lines. What is the angle between the image lines?
Hand Swap
problem

Hand swap

Age
14 to 16
Challenge level
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My train left London between 6 a.m. and 7 a.m. and arrived in Paris between 9 a.m. and 10 a.m. At the start and end of the journey the hands on my watch were in exactly the same positions but the minute hand and hour hand had swopped places. What time did the train leave London and how long did the journey take?
Similarly so
problem

Similarly so

Age
14 to 16
Challenge level
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ABCD is a square. P is the midpoint of AB and is joined to C. A line from D perpendicular to PC meets the line at the point Q. Prove AQ = AD.
Six Minutes Past Eight
problem

Six minutes past eight

Age
11 to 14
Challenge level
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Weekly Problem 45 - 2007
What is the obtuse angle between the hands of a clock at 6 minutes past 8 o'clock?