mathinschool.com
numbers and algebraic expressions
logic, sets, intervals
absolute value
function and its properties
linear function
quadratic function
polynomials
rational function
exponential function
logarithm
number sequences
limits of sequences and functions
derivative and integral of functions
trigonometry
plane geometry
analytic geometry
solid geometry
combinatorics
probability
elements of statistics
kropki game
If the triangles have equal angles then the triangles are similar. Enough check equality two angles. If the triangles have equal two angles then third must be equal too. The converse of the theorem: If the triangles are similar then corresponding angles are the same.