Stage 9 - Q1 - 2 marks
A shape has perimeter 26 cm. It is enlarged by factor 3. Find its new perimeter.
Hint
Perimeter uses the length factor, not its square.
Stage 9 - Q2 - 2 marks
A rectangle has area 70 square cm. It is enlarged by factor 2. Find the new area.
Hint
Area scales by the square of the length factor.
Stage 9 - Q3 - 3 marks
A rectangle measures 3 cm by 5 cm. Enlarge it by factor 4. Find its new perimeter and area.
Hint
The new sides are \(k\) times the original sides.
Stage 9 - Q4 - 3 marks
An enlargement changes perimeter 32 cm to 96 cm. The original area is 60 square cm. Find the image area.
Hint
First find the length factor.
Stage 9 - Q5 - 3 marks
A pupil enlarges a rectangle of area 10 square cm by factor 2, then writes area 20. Explain and correct the error.
Hint
Draw one row and one column of the enlarged rectangle.
Stage 9 - Q6 - 3 marks
A rectangle measures 5 cm by 10 cm. Enlarge it by factor 4. Find its new perimeter and area.
Hint
The new sides are \(k\) times the original sides.
Stage 9 - Q7 - 3 marks
An enlargement changes perimeter 38 cm to 114 cm. The original area is 88 square cm. Find the image area.
Hint
First find the length factor.
Stage 9 - Q8 - 4 marks
A 4 by 6 cm panel is enlarged by factor 2. Border costs USD 2 per cm and paint USD 3 per square cm. Find the combined cost.
Hint
The two parts of the price use different scaling factors.
Stage 9 - Q9 - 3 marks
A pupil enlarges a rectangle of area 77 square cm by factor 4, then writes area 308. Explain and correct the error.
Hint
Draw one row and one column of the enlarged rectangle.
Stage 9 - Q10 - 5 marks
An enlarged rectangle has perimeter 42 cm and area 108 square cm. Its scale factor from the original is 3. Find the original side lengths.
Hint
Reverse perimeter and area scaling separately, then find a suitable factor pair.