how is he related to the field of optics?
Newton lectured on optics. During this period he investigated the refraction of light, demonstrating that the multicoloured spectrum produced by a prism could be recomposed into white light by a lens and a second prism.
Isaac Newton
Newton lectured on optics. During this period he investigated the refraction of light, demonstrating that the multicoloured spectrum produced by a prism could be recomposed into white light by a lens and a second prism. 
an isosceles triangle has two sides of equal length UNANSWERABLE how did it gat the name? "Isosceles" is made from the Greek roots "isos" (equal) and "skelos" (leg). how can one find it's area? The same area formula can also be derived from Heron's formula for the area of a triangle from its three sides. where all can it be applied? Celestial mechanics what is it about? It  is the branch of astronomy that deals with the motions of objects in outer space. who all have proposed studies on it? Isaac Newton, Gottfried Leibniz, Pierre-Simon Laplace when was the first scientist born? 25 December 1642 where? Lincolnshire what were his famous findings? He formulated the laws of motion and universal gravitation. what does the latter mean? It  is usually stated as that every particle attracts every other particle in the universe with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers.
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Isaac Newton [SEP] Optics
Modern scholarship has revealed that Newton's analysis and resynthesis of white light owes a debt to corpuscular alchemy. He showed that coloured light does not change its properties by separating out a coloured beam and shining it on various objects, and that regardless of whether reflected, scattered, or transmitted, the light remains the same colour. Thus, he observed that colour is the result of objects interacting with already-coloured light rather than objects generating the colour themselves. This is known as Newton's theory of colour.