Why is it impossible to draw a triangle with two right angles?

Answer 1

Well, mathematically speaking the total degrees of a triangle adds up to 180o. So, you have used up your 180o ( right angle = 90o ) with two right angles and you have to account for another angle to have a triangle.

AnswerAll that in the above answer is correct: but it is for 'Plane' geometry, so-called because it is in a 2-dimensional plane.

However, another type of geometry is 'Spherical' geometry, called because it is in 3-dimensions like a sphere. It is used for long-range navigation on the sphere of the earth, and also in space navigation. In spherical navigation there can be more than 90O in every corner.

Surveying is one common example of the use of Plane geometry, while Spherical geometry is used for Spherical navigation, also called celestial navigation.

See Triangles p 224-226, Celestial , p 217-228, Spherical 314-329

in

'Mathematics For The Million" by Lancelot Hogben

Merlin Press 1997

ISBN 0-85036-380-2

(As far as I can tell cannot read book on Net, but plenty of firms want to sell it!)