BECE Basic Science 2024 Theory — Question 4

Model answer

1. Draw AB = 60 mm. 2. With centre A and radius 60 mm, draw an arc above AB. 3. With centre B and the same radius, draw another arc to cut the first at C. Join AC and BC. Triangle ABC is equilateral. 4. At C construct a perpendicular to AB: with centre C and any radius, cut AB at two points; from each of these points, with a larger radius, draw arcs that cross below AB; join C to the crossing point so that it cuts AB at D. 5. D is the midpoint of AB (AD = 30 mm). 6. Measure CD. By calculation: CD = √(60² - 30²) = √2700 = 51.96 mm, so CD is about 52 mm.