Lesson Plan
Curated OER

#### Indirect Proof and Inequalities in one Triangle

For Teachers 10th
In this geometry worksheet, 10th graders complete an indirect proof and order the sides or angles of a triangle. Also, students determine if a triangle can have sides with the given lengths. The two page worksheet contains twelve...
Instructional Video3:40
CK-12 Foundation

#### Indirect Proofs in Algebra and Geometry: Lesson

For Students 7th - 12th
Indirectly, it is a good proof method. A segment of a playlist on geometry introduces a way to prove geometric and algebraic statements. Using a general examples, the video shows how to develop an indirect proof.
Lesson Plan
Curated OER

#### Indirect Proof and Inequalities in One Triangle

For Teachers 10th
In this geometry worksheet, 10th graders order the sides and angles of a triangle and determine the range of the third side of a triangle given the lengths of two sides.  The one page worksheet contains sixteen questions.  Answers are...
Activity
Education Development Center

#### Sum of Rational and Irrational is Irrational

For Teachers 8th - 9th Standards
Sometimes the indirect path is best. Scholars determine whether the sum of a rational number and an irrational number is irrational. Reading a transcript of a conversation between classmates leads to an indirect proof of this concept.
Lesson Plan
Curated OER

#### Conditional Statements

For Teachers 9th - 12th
High schoolers are introduced to the topic of proofs in Geometry. During a PowerPoint presentation, they take notes on indirect proofs and have groups of students write a true statement. They are assessed on the statement and how well...
Lesson Plan
Curated OER

#### Special Segments in a Triangle

For Teachers 10th
In this geometry worksheet, 10th graders review the vocabulary associated with the special segments of a triangle and the associated points of concurrency and solve problems in which they find the indicated missing angle or segment.  The...
Worksheet
Curated OER

#### Properties of Geometry

For Students 10th
In this properties of geometry worksheet, 10th graders solve and complete 12 different problems that include various theorems. First, they draw a figure that illustrates the SAS inequality property. Then, students prove that two line...