TheMathsTutor works out the answer to the question.

TheMathsTutor works out the answer to the question.

Proving that a quadrilateral is a parallelogram if and only if its diagonals bisect each other. More free lessons at: http://www.khanacademy.org/video?v=eF6zYNzlZKQ Note: All Khan Academy content is available for free at (www.khanacademy.org)

Showing that congruent legs imply equal base angles and vice versa. More free lessons at: http://www.khanacademy.org/video?v=eF6zYNzlZKQ Note: All Khan Academy content is available for free at (www.khanacademy.org)

In a right-angled triangle the square of the hypotenuse is the sum of the squares of the other two sides. More free lessons at: http://www.khanacademy.org/video?v=eF6zYNzlZKQ Note: All Khan Academy content is available for free at (www.khanacademy.org)

In a parallelogram opposite sides and opposite angles are equal in measure.

Each exterior angle of a triangle is equal to the sum of the interior opposite angles. More free lessons at: http://www.khanacademy.org/video?v=eF6zYNzlZKQ Note: All Khan Academy content is available for free at (www.khanacademy.org)

Proof that the sum of the measures of the angles in a triangle are 180 degrees. More free lessons at: http://www.khanacademy.org/video?v=eF6zYNzlZKQ Note: All Khan Academy content is available for free at (www.khanacademy.org)

Proof that a radius is perpendicular to a chord that it bisects. More free lessons at: http://www.khanacademy.org/video?v=eF6zYNzlZKQ Note: All Khan Academy content is available for free at (www.khanacademy.org)

Proof: Angle at Centre of Circle Standing on an Arc is Twice the Angle at any Point on the Circle Standing on the Same Arc. More free lessons at: http://www.khanacademy.org/video?v=eF6zYNzlZKQ Note: All Khan Academy content is available for free at (www.khanacademy.org)

How to prove that vertically opposite angles are equal in measure. More free lessons at: http://www.khanacademy.org/video?v=eF6zYNzlZKQ Note: All Khan Academy content is available for free at (www.khanacademy.org)

How to prove that alternate angles are equal when a transversal intersects two parallel lines. This ties in with theorem 5 - two lines are parallel if and only if, for any transversal, the corresponding angles are equal. More free lessons at: http://www.khanacademy.org/video?v=eF6zYNzlZKQ Note: All Khan Academy content is available for free at (www.khanacademy.org)

How to geometrically construct the square root of 2.

How to geometrically construct the square root of 3.

A great tutorial on how to construct a Orthocentre of a triangle

A great tutorial on how to construct a Centroid of a triangle

A great tutorial on how to construct a Parallelogram, given the length of the sides and the measure of the angles

A great tutorial on how to construct a Tangent to a given circle at a given point on it

A great tutorial on how to construct a Angle of 60⁰ without using a protractor or set square

A great tutorial on how to construct a Incentre and incircle of a triangle of a given triangle

How to construct the Circumcentre and Circumcircle Of A Triangle

A great tutorial on how to construct a Rectangle given side lengths

A great tutorial on how to create a Right-angled triangle, given one side and one of the acute angles

A great tutorial on how to construct a Right-angled triangle, given length of hypotenuse and one other side

A great video tutorial on how to create a triangle with given ASA data

A great tutorial on how to create a Triangle with given SAS data

A great tutorial on what to do when you have a triangle with given lengths of 3 sides

A great tutorial on a Angle of a given number of degrees with a given ray as one arm

A great video on how to get a Line Segment Given Length On Given Ray

A great tutorial on how to make a Division of a line segment into 2, 3 or any number equal segments

A great video on how to do a Line parallel to given line, through a given point

A great tutorial on how to do a Line perpendicular to a given line l, passing through a given point on l!

A great tutorial on how to make a Line perpendicular to a given line l, passing through a given point not on l

A great tutorial on how to do Perpendicular bisector of a segment, using only compass and straight edge

A Great video explaining how to bisect an angle using only your compass and a straight edge.