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

Find the image of the triangle ABC under the homothety with center O and ratio k=-2. Draw rays from points A, B, C through point O. Find with compass point A' that line segment OA' is two times longer as OA. The ratio k is negative then A' is on different side of the point O. In the same way find point B' and C'. Join points A', B' and C'. We get the image of the triangle ABC under the homothety with center O and ratio k=-2.