Pythagorean theorem
young professor proving theorem on a blackboard b
young professor proving theorem on a blackboard b
young professor proving theorem on a blackboard b
young professor proving theorem on a blackboard b
Copybook with sketches of triangles held by geometry teacher explaining theorem
Teacher by blackboard
Youthful student pointing at blackboard during explanation of equation
Young confident teacher in eyeglasses and smart casualwear drawing angle
Young serious teacher of college or university drwing triangle on blackboard
Teacher answering questions
Making fun of teacher
Confident geometry teacher in formalwear pointing at blackboard with formulas
Math teacher explaining new topic
Explaining trigonometry
Give me little hint
Teacher at work
Confident teacher of geometry pointing at drawing of triangle on blackboard
Children or kid calculate mathematics with pencil about math with graph.
Confident teacher of geometry pointing at triangle on blackboard
Now your questions please
Young serious female teacher of geometry listening to African American student
African American student writing down algebraic equation on blackboard
Explanation of formulae
Explaining subject
