Flashcards on Similarity of triangles

Similarity of Triangles: Criteria, Properties & Applications

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What does it mean for two triangles to be similar?

Two triangles are similar if they have the same shape but not necessarily the same size.

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Similarity of Triangles

18 cards

Card 1

Question: What does it mean for two triangles to be similar?

Answer: Two triangles are similar if they have the same shape but not necessarily the same size.

Card 2

Question: What are the two conditions that must be met for two triangles to be similar?

Answer: Corresponding angles are equal, and corresponding sides are proportional.

Card 3

Question: What is the constant ratio of the lengths of corresponding sides in similar triangles called?

Answer: The ratio of similarity or scale factor, often denoted by 'k'.

Card 4

Question: If ΔABC is similar to ΔDEF (ΔABC ~ ΔDEF), how do their corresponding angles relate?

Answer: ∠A = ∠D, ∠B = ∠E, and ∠C = ∠F.

Card 5

Question: If ΔABC is similar to ΔDEF (ΔABC ~ ΔDEF), how do their corresponding sides relate?

Answer: AB / DE = BC / EF = CA / FD = k (where 'k' is the ratio of similarity).

Card 6

Question: What does a scale factor 'k' greater than 1 indicate in similar triangles?

Answer: The second triangle is an enlargement of the first.

Card 7

Question: What does a scale factor 'k' between 0 and 1 (0 < k < 1) indicate in similar triangles?

Answer: The second triangle is a reduction of the first.

Card 8

Question: What special case of similarity occurs when the scale factor 'k' equals 1?

Answer: The triangles are congruent, meaning they are identical in both shape and size.

Card 9

Question: What is the AA Similarity Theorem?

Answer: If two angles of one triangle are congruent to two angles of another triangle, then the two triangles are similar.

Card 10

Question: Why is checking just two angles sufficient for the AA Similarity Theorem?

Answer: Since the sum of angles in any triangle is 180°, if two pairs of angles are equal, the third pair must also be equal.