Introduction to vertical angles | Angles and intersecting lines | Geometry | Khan Academy

Angles (part 3) | Angles and intersecting lines | Geometry | Khan Academy

Another Valentine’s Day art lesson that looks complex but is secretly so simple. This one works beautifully for primary students and easily stretches into third through fifth grade. All it takes is a 9 x 9 square and a little line magic. Students draw a heart, add intersecting lines, and suddenly math and art are having a moment. We count the shapes inside the heart and color each one a different color. Then we count the shapes outside the heart. Every tiny shape gets its own color, which is a g

How many ways can circles overlap? - Numberphile