Similar Triangle Proofs | MathHelp.com @yourteachermathhelp

Uploaded January 2016 | Updated September 2026, 2 weeks ago

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This lesson covers similar triangle proofs. Students learn that if two angles of one triangle are congruent to two angles of another triangle, then the triangles are similar (Angle-Angle Similarity Postulate, or AA Similarity Postulate). Students also learn that the scale factor is ratio of the lengths of two corresponding sides. Students are then asked to use these concepts to determine whether given triangles are similar, and to find the missing side lengths in similar triangles.

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$Adding Mixed Numbers | MathHelp.com Need a custom math course? Visit http://www.MathHelp.com. This lesson covers adding mixed numbers. Students learn to add mixed numbers by first adding the fractions, then adding the whole numbers. For example, to add 4 2/5 + 7 4/5, first add 2/5 + 4/5 to get 6/5, then add 4 + 7 to get 11. So 4 2/5 + 7 4/5 = 11 6/5. Notice, however, that the answer, 11 6/5, contains an improper fraction, 6/5, which is the same as 1 1/5, so 11 6/5 can be rewritten as 11 + 1 1/5, which simplifies to 12 1/5. So 4 2/5 + 7 4/5 = 12 1/5. Note that some of the problems in this lesson also require the student to find a common denominator for the fractions. For example, 5 1/4 + 6 3/8.$

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