- An triangle has three acute angles. An
triangle has one obtuse angle. A triangle has
one right angle. - The longest side of a right triangle is called the
. The other two sides of a right triangle are
called. - The angles of an isosceles triangle have the
same measure. The sides of equal length of an
isosceles triangle form the angle. - In this section, we discussed the sum of the measures
of the angles of a triangle. The word sumindicates the
operation of. - Complete the table.
- Draw an example of each type of triangle.
a. isosceles b. equilateral
c. scalene d. obtusee. right f. acute- Classify each triangle as an acute, an obtuse, or a right
triangle.
a. b.
c. d.- Refer to the triangle shown below.
a. What is the measure
of?
b. What type of triangle
is it?
c. What two line
segments form the legs?
d. What line segment is the hypotenuse?
e. Which side of the triangle is the longest?
f. Which side is opposite? - Fill in the blanks.
a. The sides of a right triangle that are adjacent to
the right angle are called the.
b. The hypotenuse of a right triangle is the side
the right angle. - Fill in the blanks.
a. The triangle theorem states that if two
sides of a triangle are congruent, then the angles
opposite those sides are congruent.
b. The of the isosceles triangle theorem
states that if two angles of a triangle are
congruent, then the sides opposite the angles have
the same length, and the triangle is isosceles. - Refer to the given triangle.
a. What two sides are of
equal length?
b. What type of triangle is
XYZ?
B
B
91 °90 °742 Chapter 9 An Introduction to Geometry
Number of Sides Name of Polygon
3 4 5 6 7 8 910
12CONCEPTS
- Draw an example of each type of regular polygon.
a. hexagon b. octagon
c. quadrilateral d. trianglee. pentagon f. decagon- Refer to the triangle below.
a. What are the names of the vertices of the
triangle?
b. How many sides does the triangle have?
Name them.
c. Use the vertices to name this triangle in three
ways.
HJIA CBZYX