Stage 9 - Q1 - 4 marks
Find the total surface area of the closed right-triangular prism.
Hint
Surface area includes every external face.
Stage 9 - Q2 - 3 marks
A triangular tube has right-triangle sides 9, 12, 15 cm and length 16 cm. Both triangular ends are open. Find the material area.
Hint
List the faces that are actually present.
Stage 9 - Q3 - 4 marks
Find the total surface area of the closed right-triangular prism.
Hint
Surface area includes every external face.
Stage 9 - Q4 - 4 marks
A closed prism has a right-triangular end with legs 12, 16 cm and length 12 cm. A pupil gives 336 square cm. Explain the missing faces and correct it.
Hint
A closed triangular prism has five faces.
Stage 9 - Q5 - 4 marks
A closed triangular prism has right-triangle sides 3, 4, 5 cm and surface area 204 square cm. Find its length.
Hint
The three rectangles together have area perimeter×length.
Stage 9 - Q6 - 3 marks
A triangular tube has right-triangle sides 9, 12, 15 cm and length 19 cm. Both triangular ends are open. Find the material area.
Hint
List the faces that are actually present.
Stage 9 - Q7 - 4 marks
A closed prism has right-triangle sides 15, 20, 25 cm and length 5 cm. Coating costs 3 cents per square cm. Find the cost in USD.
Hint
A material cost uses surface area, not volume.
Stage 9 - Q8 - 4 marks
A closed triangular prism has right-triangle sides 6, 8, 10 cm and surface area 264 square cm. Find its length.
Hint
The three rectangles together have area perimeter×length.
Stage 9 - Q9 - 4 marks
A closed prism has a right-triangular end with legs 6, 8 cm and length 6 cm. A pupil gives 84 square cm. Explain the missing faces and correct it.
Hint
A closed triangular prism has five faces.
Stage 9 - Q10 - 6 marks
Two identical closed right triangular prisms have triangle sides 6, 8, 10 cm and prism length 15 cm. They are joined perfectly along one 6 cm by 15 cm rectangular face each. Find the external surface area of the combined solid.
Hint
A joining face becomes internal on both solids.