Question 1
(a) The circumference of a circle is 115.
(i) Determine by construction the diameter of the circle
(ii) Measure and state the length of the diameter.
(b)
(i) Construct and escribed circle to a triangle of sides 50, 65 and 75 to touch the shortest side of the triangle.
(ii) Measure and the state the radius of the circle.
Observation
Candidates were able to determine the diameter of the circle whose circumference was given as 115. A few candidates, however, could not adequately draw the required escribed circle to the given triangle. The solution of the poorly answered question is given below
Question 1A
(b) CONSTRUCTION OF ESCRIBED CIRCLE TO A TRIANGLE
WITH GIVEN SIDES
MAJOR REQUIREMENTS INVOLVED IN CONSTRUCTING THE ESCRIBED CIRCLE
- Drawing the triangle ABC with the given dimension AB = 75, BC = 50, AC = 65
- Extending AB and AC to D and E respectively
- Bisecting angles CBD and BCE
- Locating point 0 as the intersection of the
- Dropping a perpendicular from point 0 to cut BD at F. OF is the radius of the escribed circle
- Drawing the escribed circle using radius OF at cente O
- Drawing the escribed circle at the shortest side CB
- Measuring & stating the radius of the escribed circle = 36±1
- Neatness and quality of linework