EXERCISES AND GAMES
Geometry
 
1. CONSOLIDATION EXERCISES
 

17.- Change the values of r, h and k to make the red circle fit exactly over each of the other four circles in the diagram.
 
Write the values directly into the boxes and click on the Enter key after each one.

 

18.- Draw the circles of these equations:

x²+y²=6²
(x-2)²+(y+3)²=36
(x+5)²+(y-1)²=3²
(x+2)²+(y+3)²=25
2. RELATING EQUATIONS TO SHAPES
When you become familiar with the subject you only have to look at the equation to know immediately where the circle should be located on the plane.
19.- Change the values of r, h and k to make the blue circle fit exactly over each of the other four circles in the diagram.
 
Use the coloured arrows next to the zoom, 0.x and 0.y keys
The Init button will restore the initial values.

20.- Match the pairs from the left and right columns. Check your results by drawing each of the circles:
Concentric with the red  (x+3)²+y²=4²
Tangent to the green x²+(y-4)²=25
Concentric with the black  (x-5)²+(y-2)²=4
Tangent to the green and the orange x²+(y+4)²=16

3. PLAYING WITH STRAIGHT LINES AND CIRCLES

Make the most of the interactive nature of the program to refresh your memory of some things you have already learnt about how straight lines and circles relate to each other.
21.- Write in the values for the parameters of the straight line and circle so that the line goes through the origin and point A and point A is the centre of the circle.
 
Write the values into the corresponding boxes "by hand" and click on the enter key after each one. Click on the init key to start a new exercise.

22.- Write in the values of the parameters of the straight line and circle so that the line goes through the origin and point A and origin is the centre of the circle, which also goes through point A.
 

 

       
           
  Jesús Fernández Martín de los Santos
 
Spanish Ministry of Education. Year 2001
 
 

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