TOPIC-SHAPES&angles

BY:- MRS.M.ghosh

CLASS –VMATHS

PART 1SOLID SHAPES

Two-dimensional Shapes (2D)

• These shapes are flat and can only be drawn on paper.

• They have two dimensions – length and width.

• They are sometimes called plane shapes.

Objective:

To describe properties of solid shapes

such as perpendicular and parallel lines, faces and edges

Three-dimensional Shapes (3D)

• These shapes are solid or hollow.

• They have three dimensions – length, width and height.

Face

• Part of a shape that is flat.(Or curved)

• E.g. A cube has 6 of these.

Edge• The line where two

faces meet.• E.g. A cube has 12 of

these.

Vertex (Vertices)

• The place where three or more edges meet.

• This pyramid has 4 of these.

Parallel• These type of lines

stay the same distance apart for their whole length. They do not need to be straight or the same length.

Perpendicular• A line that is drawn in

a right angle to another line .

• In solid shapes edges could be at a right angle to one another.

• Faces could also be at right angles to one another.

Cube• A three-dimensional

shape which has 6 square faces all the same size.

Some faces parallel

Some edges parallel

Some faces perpendicular

Some edges perpendicular

Cuboid• A three-dimensional

shape which has 6 rectangular faces.

Some faces parallel

Some edges parallel

Some faces perpendicular

Some edges perpendicular

Sphere• A perfectly round

three-dimensional shape, like a ball. It has only one curved face.

No perpendicular faces or edges

No parallel faces or edges

Hemisphere• A three-dimensional

shape that is half a sphere.

No parallel faces or edges

No perpendicular faces or edges

Cone• A three dimensional

shape with a circle at its base and a pointed vertex.

No perpendicular faces or edges

No parallel faces or edges

Cylinder• A three-dimensional

shape with circular ends of equal size.

Some faces parallel

Some edges parallel

Some faces perpendicular

No edges perpendicular

PART 2

PLANE SHAPES

PolygonsTwo-dimensional shapes

that have sides made from straight lines.

• E.g. triangles squares hexagons

Quadrilaterals• Any two-dimensional

shapes with four straight sides.

• E.g. square rhombus rectangle trapezium kite

Rectangle• A four sided two-

dimensional shape with two pairs of parallel sides that meet at right angles.

Kite• A two-dimensional

shape with two shorter sides of equal length and two longer sides of equal length.

Rhombus• A two-dimensional

four sided shape with opposite sides that are parallel and all the sides are the same length.

Trapezium• A two-dimensional

shape with four sides.One pair of sides is parallel with one side longer than the other.

Pentagon• A two-dimensional

shape with five straight sides and five angles.

Hexagon• A two-dimensional

shape with 6 straight sides and 6 angles.

Octagon• A two-dimensional

shape with 8 straight sides and 8 angles.

Circle• A round flat two-

dimensional shape.

Square• Two dimensional

shape with 4 sides of the same length and 4 90° angles.

Triangle• Two-dimensional

shape with three straight sides and three angles.

• Can you name 4 different kinds?

BASIC TERMS OF GEOMETRY

Line

A line goes on and on in both directions. A line is drawn with an arrow on each end

This is called a point!

When it’s at the end of a line it is called an endpoint!

Line Segment

A line segment is a part of a line. It is drawn with two endpoints

Ray

A ray goes on and on in one direction. It is drawn with an arrow on one end and an endpoint on the other.

• Angle – Two rays or two line segments that meet at a common end point.

DEFINITION

Arm of angle

Arm of angle

vertexB C

A

Vertex of the angle :- B Arms of the angle :-- BA BC Naming of the angle :-- ABC or CBA or B

TYPES OF ANGLES

1. Zero Angle Measure is 0°

2. Acute Angle Measure is more

than 0° but less than 90 °

5. Straight Angle Measure is 180°

7. Complete Angle Measure is 360°

6. Reflex Angle Measure is more

than 180° but less than 360 °

Fractions for turns.

•90° = ¼ turn•180° = ½ turn•270° = ¾ turn•360° =1

Use of Protractor for constructing an angle

What do we use to measure an angle?

Here is a standard protractor like you use in the classroom.

A protractor

When we use a protractor, we need to line it up correctly.

You need to make sure the protractor is lined up correctly.

Is this ready to measure the angle?

Were you right......................it wasn’t

Look for the upside down ‘T’ in the middle of the straight line on your protractor.

This needs to be exactly on the vertex of your angle.

We need to remember.....

It doesn’t matter which way round the angle is, you ALWAYS need to line the upsidedown ‘T’ to the vertexof the angle.

Now you are ready.

Read from the 0°, and follow the inner set of numbers.

Once you reach 30° you need to be careful!!!

You then need to look at the 1° markings on the outer set of numbers.

What does it measure?

This angle measures 35°.

What does it measure?

This angle measures 60°.

What does it measure?

This angle measures 110°.