4A - Relationships of Triangles, Congruence, & Similarity

Classify the Triangles below by their angles and sides.

Groups:

(a) Right Isosceles

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(b) Equiangular Equilateral

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(c) Obtuse Scalene

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Find the measures of the sides of ΔABC, then classify it by its sides.

A (1,13), B (3,3), C (10, -6)

HINT: use the distance formula

• Equilateral

• Isosceles

• Scalene

Using the theorem for the sum of the interior angles of a triangle, find the third angle for each triangle in the table below.

a

e

c

58°

64°

48°

80°

70°

Using the theorem for sum of interior angles of a triangle, find the measure of ∠A.

• 12

• 48

• 59

Determine the measure of each base angle in the triangle.

• 65°

• 70°

• 140°

Find the length of PQ if Δ PQR is an isosceles with PQ ≅ QR.

• 11

• 22

• 43

Δ ABC has coordinates A (-4,2), B (0,4), and C (-4,2).

Find the midpoint of AC.

HINT: use the midpoint formula

• (0,2)

• (-2,4)

• (4,0)

If DE, EF, and DF are midsegments of Δ ABC, what is the perimeter of triangle ABC?

PERIMETER FORMULA: add all sides

• 106

• 108

• 110

• 14

• 28

• 56

Using the Converse of Pythagorean Theorem, identify if the three squares will form a right triangle or NOT. Select the correct answer in each row.

Groups:

(a) Forms a Right Triangle

,

(b) Does NOT Form a Right Triangle

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