...that the three angles of a, triangle are equal to two right angles, or that in a right angled triangle the square of the hypothenuse equals the sum of the squares of the legs, and, with some previous training and preparation, he may be able to construct an original...

...that the three angles of a triangle are equal to two right angles, or that in a right-angled triangle the square of the hypothenuse equals the sum of the squares of the legs, and, with some previous training and preparation, he may be able to construct an original...