Angles - points, lines and parallel lines

There are 80 NRICH Mathematical resources connected to Angles - points, lines and parallel lines
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?
Quad in Quad
problem

Quad in Quad

Age
14 to 18
Challenge level
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Join the midpoints of a quadrilateral to get a new quadrilateral. What is special about it?
A Problem of time
problem

A Problem of time

Age
14 to 16
Challenge level
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Consider a watch face which has identical hands and identical marks for the hours. It is opposite to a mirror. When is the time as read direct and in the mirror exactly the same between 6 and 7?
Flexi Quads
problem

Flexi Quads

Age
16 to 18
Challenge level
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A quadrilateral changes shape with the edge lengths constant. Show the scalar product of the diagonals is constant. If the diagonals are perpendicular in one position are they always perpendicular?
Square World
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Square World

Age
16 to 18
Challenge level
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P is a point inside a square ABCD such that PA= 1, PB = 2 and PC = 3. How big is angle APB ?
Clock Hands
problem

Clock Hands

Age
7 to 11
Challenge level
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This investigation explores using different shapes as the hands of the clock. What things occur as the the hands move.
Making Maths: Clinometer
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Making Maths: Clinometer

You can use a clinometer to measure the height of tall things that you can't possibly reach to the top of, Make a clinometer and use it to help you estimate the heights of tall objects.
Watch those Wheels
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Watch those Wheels

Have you ever noticed the patterns in car wheel trims? These questions will make you look at car wheels in a different way!