Quadratic equations

There are 39 NRICH Mathematical resources connected to Quadratic equations
Halving the Triangle
problem

Halving the triangle

Age
16 to 18
Challenge level
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Draw any triangle PQR. Find points A, B and C, one on each side of the triangle, such that the area of triangle ABC is a given fraction of the area of triangle PQR.
Two Cubes
problem

Two cubes

Age
14 to 16
Challenge level
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Two cubes, each with integral side lengths, have a combined volume equal to the total of the lengths of their edges. How big are the cubes? [If you find a result by 'trial and error' you'll need to prove you have found all possible solutions.]
Xtra
problem

Xtra

Age
14 to 18
Challenge level
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Find the sides of an equilateral triangle ABC where a trapezium BCPQ is drawn with BP=CQ=2 , PQ=1 and AP+AQ=sqrt7 . Note: there are 2 possible interpretations.
Kissing
problem

Kissing

Age
16 to 18
Challenge level
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Two perpendicular lines are tangential to two identical circles that touch. What is the largest circle that can be placed in between the two lines and the two circles and how would you construct it?
Good Approximations
problem

Good approximations

Age
16 to 18
Challenge level
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Solve quadratic equations and use continued fractions to find rational approximations to irrational numbers.
Golden Fibs
problem

Golden fibs

Age
16 to 18
Challenge level
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When is a Fibonacci sequence also a geometric sequence? When the ratio of successive terms is the golden ratio!
Polar Flower
problem

Polar flower

Age
16 to 18
Challenge level
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This polar equation is a quadratic. Plot the graph given by each factor to draw the flower.
Target Six
problem

Target six

Age
16 to 18
Challenge level
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Show that x = 1 is a solution of the equation x^(3/2) - 8x^(-3/2) = 7 and find all other solutions.
Golden Construction
problem

Golden construction

Age
16 to 18
Challenge level
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Draw a square and an arc of a circle and construct the Golden rectangle. Find the value of the Golden Ratio.
Darts and Kites
problem

Darts and kites

Age
14 to 16
Challenge level
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Explore the geometry of these dart and kite shapes!