Three sided closed figure whose internal angles are either acute or obtuse angles called as triangles. Triangle is a very important geometrical figure will be discussed more often in elementary, middle and high schools.

Elementary school kids may study about classification of triangles by sides and angles, finding the missing angles and more; where as middle school children learn about Pythagorean theorem, area of triangles, perimeter and more.

Free triangle worksheets in this page may help you to review or practice problems based on triangles.

Classification of Triangles by its Sides:

We can classify triangles based on sides such as equilateral, isosceles and scalene. In equilateral triangle all sides are equal, in isoceles any two sides are equal where as in scalene all sides are different.

Classification of Triangles by its Angles:

Triangles can be classified based on anlges such as acute, obtuse and right-angled triangle. In acute triangle all angles are acute; in obtuse, any one the angle is obtuse and other two angles are acute, in right angled triangle, one angle is 90 degree.

Find the Missing Angles of the Triangles:

Sum of the angles of any triangle is 180 degree. Find the missing angle by taking the difference between 180 and sum of other two angles.

Pythagorean Theorem Worksheets:

According to Pythagorean Theorem, in a right-angled triangle, square of the hypotenuse equals sum of the squares of other two sides.

Perimeter of Triangle Worksheets:

Perimeter worksheets for triangles based on figures and dimensions are provided here. Perimeter can be find by adding all the three sides.

Area of Triangle Worksheets:

Area of triangles worksheets based on base and height is provide here. Use the formula given above to solve these worksheets.

Area of Right Triangle Worksheets:

Same formula is applicable even here. We usually call the longest side as hypoteneuse and other sides as legs. So, A = 1/2 * leg 1 * leg 2

Area of Scalene Triangle Worksheets:

Area of scalene triangles can be find using Heron's formula or Hero's formula. More concentration is required when you calculate in paper or calculator. Formula is provided in worksheets. These worksheets are suitable for grade 6 and up.

Area of Equilateral Triangle Worksheets:

When the base and height of the equilateral triangle is given, then we use general formula. In case, only side of an equilateral triangle is given, use A = sqrt(3)/4 * a^2, where a is the side of an equilateral triangle.