10 questions · Form 3 Mathematics Bab 3: Scale Drawings
A drawing length of 4 cm represents an actual length of 20 cm. What is the scale of the drawing?
Prefer reading to quizzing? All 10 questions are listed below with the answer and explanation under each one.
1. A drawing length of 4 cm represents an actual length of 20 cm. What is the scale of the drawing?
Answer: C
Scale = 1 : n where n = Actual / Drawing = 204 = 5. Thus, the scale is 1 : 5.
2. A bridge of actual length 150 m is drawn to a scale of 1 : 3,000. Calculate the length of the bridge on the drawing in centimetres.
Answer: A
Actual length = 150 m = 15,000 cm. Drawing length = 15,0003,000 = 5 cm.
3. Which of the following grid transformations results in a scale drawing with scale 1 : 3?
Answer: A
A scale of 1 : 3 means every drawing dimension is 13 of the corresponding actual object dimension.
4. Which property remains completely unchanged when an object is drawn to scale?
Answer: C
Angles are invariant in scale drawings; corresponding angles in a scale drawing are identical to those in the original object.
5. If a right-angled triangle has sides of 3 cm, 4 cm, and 5 cm in a scale drawing of scale 1 : 10, what is the length of its actual hypotenuse?
Answer: A
The hypotenuse in the drawing is 5 cm. Actual hypotenuse = 5 cm × 10 = 50 cm.
6. A rectangular room measures 8 m by 6 m. If it is drawn using a scale of 1 : 100, what are its dimensions on the drawing?
Answer: A
Convert dimensions to cm: 800 cm and 600 cm. Drawing length = 800100 = 8 cm; Drawing width = 600100 = 6 cm.
7. If the scale of a map is 1 : 100, and a garden has an area of 5 cm² on the map, what is the actual area of the garden in square metres?
Answer: A
Actual Area = Drawing Area × n² = 5 cm² × (100)² = 5 × 10,000 = 50,000 cm². Converting to m²: 50,00010,000 = 5 m².
8. A cell length of 0.02 mm is drawn with a length of 4 cm. What is the scale of the drawing in the form 1 : n?
Answer: B
Convert 4 cm to mm = 40 mm. Scale ratio = Drawing : Object = 40 : 0.02 = 1 : (0.0240) = 1 : 0.0005 or 1 : 1200.
9. The height of a building on a blueprint drawn with a scale of 1 : 200 is 15 cm. What is the actual height of the building in metres?
Answer: A
Actual length = 15 cm × 200 = 3,000 cm. Converting to metres: 3,000100 = 30 m.
10. If a scale is given as 1 : n where n < 1, what can be deduced about the scale drawing relative to the actual object?
Answer: B
When n < 1 (e.g., 1 : 0.5), the drawing length is greater than the actual object length, meaning the drawing is enlarged.