Properties of Triangle
Properties of triangle are discussed here:
Property 1: The sum of three angles of a triangle equals to 180°.
In each case, the sum of the measures of angles equals to 180°. So if two angles of a triangle are given, we can easily find out its third angle.
1. In a right triangle, if one angle is 50°, find its third angle.
∆ PQR is a right triangle, that is, one angle is right angle.
Given, ∠PQR = 90°
∠QPR = 50°
Therefore, ∠QRP = 180° - (∠Q + ∠ P)
= 180° - (90° + 50°)
= 180° - 140°
∠ R = 40°
Property :The sum of the length of any two sides of a triangle is greater than the length of the third side.
In each case, if we add up any two sides of the ∆, the sum is more than its third side.
1. Is it possible to have a triangle whose sides are 5 cm, 6 cm and 4 cm?
The lengths of the sides are 5 cm, 6 cm, 4 cm,
(a) 5 cm + 6 cm > 4 cm.
(b) 6 cm + 4 cm > 5 cm.
(c) 5 cm + 4 cm > 6cm.
Hence, a triangle with these sides is possible.2.
Is the construction of a triangle possible in which the lengths of sides are 5 cm, 4 cm and 9 cm?Solution:
The lengths of the sides are 5 cm, 4 cm, 9 cm.
5 cm + 4 cm = 9 cm.
Then the sum of two smaller sides is equal to the third side. But in a triangle, the sum of any two sides should be greater than the third side.
Hence, no triangle possible with sides 5 cm, 4 cm and 9 cm.● Triangle.
Classification of Triangle.
Properties of Triangle.
Worksheet on Triangle.
To Construct a Triangle whose Three Sides are given.
To Construct a Triangle when Two of its Sides and the
included Angles are given.
To Construct a Triangle when Two of its Angles and the
included Side are given.
To Construct a Right Triangle when its Hypotenuse and One
Side are given.
Worksheet on Construction of Triangles.
5th Grade Geometry Page
5th Grade Math Problems
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