I need help please and don't answer if your going to give me a file.

chemists are often responsible for designing a chemical reaction and analyzing the products obtained from it. one significant part of designing a chemical reaction is determining the amount of each reactant that is needed and the amount of each product that will be produced. in order to do so, chemists use stoichiometry, the quantitative relationships between reactants and products.

triangle eg 7.5 × cos "a" or 7.5 × sin "b" or 6 tan"a"

it changed by a factor of 2.

the measure of the unknown angle is 7.5