1
GEOMETRIC FIGURES 1
Triangles
Supplementary and Complementary Angles
If the sum of the measures of two angles is 180°, then the angles are
supplementary.
If angle A and angle B are supplementary, then ∠ ∠
A + B = 180°
If the sum of the measures of two angles is 90°, then the angles are
complementary.
If angle A and angle B are complementary, then ∠ ∠
A + B = 90°
Equilateral triangles vs. Isosceles triangle
B B
A C A C
b
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, 2
Isosceles triangles Equilateral triangles
Two equal sides All three sides are equal
Base angles are equal All three angles = 60°
Question 1
^ ^
Construct ΔDEF with EF = 7 cm, E = 50° and F = 50°.
^
Also construct ΔJKL with JK = 6 cm, KL = 6 cm and J = 70°.
Measure and label all the sides and angles of each triangle.
These are triangles, because
.
www.smartculture-education.com
GEOMETRIC FIGURES 1
Triangles
Supplementary and Complementary Angles
If the sum of the measures of two angles is 180°, then the angles are
supplementary.
If angle A and angle B are supplementary, then ∠ ∠
A + B = 180°
If the sum of the measures of two angles is 90°, then the angles are
complementary.
If angle A and angle B are complementary, then ∠ ∠
A + B = 90°
Equilateral triangles vs. Isosceles triangle
B B
A C A C
b
www.smartculture-education.com
, 2
Isosceles triangles Equilateral triangles
Two equal sides All three sides are equal
Base angles are equal All three angles = 60°
Question 1
^ ^
Construct ΔDEF with EF = 7 cm, E = 50° and F = 50°.
^
Also construct ΔJKL with JK = 6 cm, KL = 6 cm and J = 70°.
Measure and label all the sides and angles of each triangle.
These are triangles, because
.
www.smartculture-education.com
