Ключевые слова: angle, background, board, centimeter, chalk, chalkboard, closeup, college, color, copy, design, drafting, drawing, education, engineering, equipment, female, geometry, green, hands, item, knowledge, learning, length, line, markings, math, mathematical, mathematics, measure, measuring, number, person, protractor, ruler, school, shape, space, stationery, study, supplies, teach, text, tool, top, triangle, university, view, woman, work,