Friday, February 22, 2013

6th Grade Geometry Problems

Introduction:

Sixth grade geometric contains the basic of geometricals .It includes the topic of geometric in Points, Lines ,Line segment, Triangles, Types of triangles, circles, Angles, Types of Angles, Quadrilaterals

Geometric Definitions:

Point: A point   determines the location of particular area.

Line:   A line through two points A and B is written as AB.. It extends

Indefinitely in both directions. So it contains countless number of points. Two points are enough to fix a line

Types of lines:

Intersecting lines
Parallel lines
Perpendicular lines

Triangles in Geometry:


Triangles:

A triangle is a three-sided polygon. In fact, it is the polygon with the least number of sides

Types of Triangle:

Equilateral Triangle
When all the three sides of a triangle are equal to each other, it is called an Equilateral triangle. Each angle measures to 60 degrees. It is a type of regular polygon.

Isosceles Triangle
When two sides of a triangle are equal it is called an Isosceles triangle. It also have two equal angles.

Scalene Triangle
When no two sides of a triangle are equal the triangle is called Scalene triangle. It has three unequal sides.

Area of triangle: 1/2(Base*Height)

Perimeter of Triangle: (Sum of three sides)

Example problem:

1.Find the area of triangle base is 4cm,height is 2cm

Solution:

Area=1/2(4*2)

=8/2

=4cm2

2.Find perimeter of Triangle side lengths are 5cm,5cm,8cm

Solution:

Perimeter=(A+B+C)(Sum of three side lengths)

A=5, B=5, C=8

=(A+B+C)

=5+5+8

=18cm


Angles and Circle in Geometry


Angle:

Right Triangle
. Right angle is equal to 90 degrees. It obeys Pythagoras theorem.

Acute angle
. Acute angle is an angle which is less than 90 degrees.

Obtuse angle
An Obtuse angle is an angle which is greater than 90 degrees but less than 180 degrees.

Acute angle:
Acute and Obtuse triangles are also called as Oblique triangles because they don’t have any angle measuring 90 degrees.

Quadrilateral:
A four sided polygon is a quadrilateral. It has sides and 4 angles

Circle:

Are of circle=Pi*r*r

Circumference of Triangle=2*Pi*r

Diameter=2*Radius

Example:

Find the area  and circumference of the circle when the radius is 4cm?

Solution:

1.     Area=Pi*r*r (r=4) (Pi=3.14 constant)

=3.14*4*4

=50.24cm2

2. Circumference =2*pi*r

=2*3.14*4

=25.12cm

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