Geometry and angle theorems

You may not measure; you may use facts. Angles on a line, at a point, vertically opposite, the triangle sum, isosceles base angles, and the exterior-angle theorem. Students chase angles in a diagram with one or two given measures, name the special quadrilaterals, and construct a triangle given SAS or ASA.

Specification · for a parent or teacher
Part no.
angle-theorems-triangles
Course
Advanced Math 5 · Unit 11
Realm
Shapes
Difficulty
3 of 4 Grade 6–7 core. Multi-step, first symbolic work.
Qty
3 items

Part no. is the node's id; the realm is the kind of math; qty is how many practice items it carries.

Students can

chase angles in a diagram with one or two given measures; name parallelogram, rhombus, trapezoid, rectangle, square; construct a triangle given SAS or ASA with ruler and protractor.

Ready when

a diagram with two lines crossing and a triangle on one ray, one 35° labeled, all other angles found with reasons.

Formulas

Triangle sum
A+B+C=180\angle A + \angle B + \angle C = 180^\circ
Exterior angle
exterior=sum of the two remote interior angles\text{exterior} = \text{sum of the two remote interior angles}

Watch for

exterior angle treated as 180180^\circ minus one interior; “vertically opposite” used on adjacent angles.

Before · requires

After · used by

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angle-theorems-triangles

Items: angle-theorems-triangles-01 · angle-theorems-triangles-02 · angle-theorems-triangles-03