A few tools that fashion designers use are:
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im not a fashion designer but im guessing that fashion designers do use geometry when they are sowing clothes or designing them
they use it to get the right size of fabric to use
algebra, calculus, arithmetic, etc.
Fashion designers need to measure the fabric they use. They use fractions and decimals to figure how much they need.
Einstein used tools to make his inventions. He probably use an old fashion microscope to study microscopic things but that is all that I know:( Hope it answered your question!