¶ Spherical Triangle Sequence (1)
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Index Entry
Spherical Triangle Sequence:
"I often ask a young student to draw a triangle and, when he says, ‘Where shall I draw it?’ I say, ‘Draw it on the ground.’ So he scratches a triangle and I say, ‘You have drawn four triangles: When you draw on the Earth you must recognize that the Earth is a great sphere. As a sphere it is a closed or finite surface in contrast to the infinity of the plane. You will agree with me when I make a closed line around the middle of the Earth (that is, I delineate the equator) that this will divide the Earth into two finite and equally valid areas, a northern and a southern hemisphere. If I made a lesser circle north of the equator it would still run around and close back on itself and divide the Earth’s surface into two unequal areas, a smaller northerly and a larger southerly area, simply because I have divided the total unitary and finite surface of the sphere into two sub-areas.’ So when a student draws a triangle for me on the unitary, closed finite surface of our spherical planet, he divides the total area of our sphere into two sub-areas, one very large and one very small, both triangular.
“Now we begin the slide projections and as you will discover”
