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Classifying Triangles Worksheet

Classifying Triangles Worksheet
  • Page 1
 1.  
Which of the figures appears to be a right triangle?

a.
Figure 2
b.
Figure 4
c.
Figure 1
d.
Figure 3


Solution:

A right triangle has one 90° internal angle (a right angle).

One of the angles in Figure 3 measures 90°.

Figure 3 is a right triangle.


Correct answer : (4)
 2.  
Identify the hypotenuse of the ΔPQR.


a.
side PQ
b.
angle P
c.
side QR
d.
angle Q


Solution:

In a right triangle, the side opposite to the right angle is the hypotenuse; it is the longest side in the right triangle.

In the figure, QPR is the right angle.

The side opposite to QPR is QR.

Side QR is the hypotenuse of the ΔPQR.


Correct answer : (3)
 3.  
Which of these is an acute angle in ΔABC?

a.
BCA
b.
ABC
c.
CBA
d.
ACA


Solution:

ΔABC represents a right triangle with one right angle, ABC and two acute angles, BCA and BAC.

BCA is an acute angle in ΔABC.


Correct answer : (1)
 4.  
Identify the leg(s) in the triangle ABC.

a.
AB
b.
AB, BC
c.
AB, AC
d.
AC, BC


Solution:

In the triangle ABC, AC is the hypotenuse.
[The side opposite to the right angle is the hypotenuse; it is the longest side in the right triangle.]

AB and BC are the legs of the triangle ABC.
[The other two sides are the legs of the triangle.]


Correct answer : (2)
 5.  
Which of these is the longest side in the right triangle shown?

a.
side LM
b.
side KL
c.
All sides are equal
d.
side KM


Solution:

In a right triangle, the side opposite to the right angle is the hypotenuse; it is the longest side in the right triangle.

KLM is the right angle.

The side opposite to KLM is KM.

Side KM is the longest side in the right triangle.


Correct answer : (4)
 6.  
Classify the triangle by the measure of its angles.


a.
acute triangle
b.
straight
c.
obtuse triangle
d.
right triangle


Solution:

When one angle of a triangle is greater than 90°, the triangle is called an obtuse angled triangle.

In the figure, one of the angles is 110° which is greater than 90°.

Therefore, the triangle is an obtuse triangle.


Correct answer : (3)
 7.  
A triangle having all its sides of equal length is called an _______ triangle.
a.
isosceles
b.
equal
c.
equilateral
d.
scalene


Solution:

A triangle having all sides of equal length is known as an equilateral triangle.


Correct answer : (3)
 8.  
A triangle having two sides of equal length is known as an _________ triangle.
a.
acute angle
b.
isosceles
c.
scalene
d.
equilateral


Solution:

A triangle having two sides of equal lengths is called an isosceles triangle.


Correct answer : (2)
 9.  
A triangle having all its sides of different lengths is known as _______ triangle.
a.
isosceles
b.
equilateral
c.
scalene
d.
unequal


Solution:

A triangle having all sides of different lengths is known as a scalene triangle.


Correct answer : (3)
 10.  
When all the angles of a triangle are less than 90°, the triangle is known as an _____ triangle.
a.
obtuse triangle
b.
straight triangle
c.
acute triangle
d.
right triangle


Solution:

When all the angles of a triangle are less than 90°, the triangle is known as an acute triangle.


Correct answer : (3)

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