TRIANGLE
Definition Of Triangle
A three-sided polygon is called to be a triangle
A Triangle is a polygon with three sides
More About Triangles
Equilateral Triangle: A triangle with all the sides of same length is called equilateral triangle.
Isosceles Triangle: A three-sided polygon with at least two sides of the same length is called isosceles triangle.
Scalene Triangle: A three-sided polygon with no sides of the same length is called scalene triangle.
Right Triangle: A three-sided polygon with one right angle is called right triangle.
Acute Triangle: A triangle measuring all its angles less than 90o is called acute triangle.A three-sided polygon with all its angles less than 90o is called
acute triangle.
Obtuse Triangle: A triangle with one of its angle measuring more than 90o is called obtuse triangle.
Video Examples: Triangles
Examples of Triangle
Solved Example on Triangle
Ques: A piece of land is in the shape of a triangle with the sides of length 5 m, 5 m and 3 m? What is this triangle called?
Choices:
A. right triangle
B. scalene triangle
C. isosceles triangle
D. equilateral triangle
Correct answer: C
Solution:
Step 1: Two of the three sides are equal to 5 m.
Step 2: Since two sides are equal, the land is in the form of an isosceles triangle.
Quick Summary
- A triangle has three sides and three angles.
- The sum of the angles in a triangle is always 180 degrees.
- Triangles can be classified by their sides (equilateral, isosceles, scalene) or by their angles (acute, right, obtuse).
⚠️ Common Mistakes
- Confusing isosceles and equilateral triangles.
- Assuming all triangles are the same.
- Forgetting that the angles must sum to 180 degrees.
🌍 Real-World Uses
- Structural support in bridges, distributing weight across a wider area.
- Triangulation in surveying and navigation to determine precise locations.
- Architecture, where triangular shapes are used in roof design for stability and aesthetics.
📋 Standards Alignment
CCSS.MATH.CONTENT.4.G.A.2
🔗 Related Links
🍎 Teacher Insights
Use visual aids and real-world examples to help students understand the different types of triangles. Hands-on activities, like constructing triangles with straws or paper, can also be very effective.🎓 Prerequisites
- Basic shapes
- Counting to three
Check Your Knowledge
Q1: A triangle has sides of length 5, 5, and 3. What type of triangle is it?
Q2: What is the sum of angles in a triangle?
Frequently Asked Questions
Q: What is an equilateral triangle?
A: An equilateral triangle has all three sides of equal length and all three angles equal to 60 degrees.
Q: What is a right triangle?
A: A right triangle has one angle that measures 90 degrees.