Finding an Unknown Angle

Teach your class how to apply their knowledge of geometry as they explore the unknown. In order to find an unknown angle, students must understand that rectangles have four interior right angles, that right angles have 90 degrees, and that angle measurement is additive. For fifth and sixth graders use this as an opportunity to practice writing and solving simple addition algebra equations. A problem that would make a nice formative assessment in a unit quadrilaterals.