P5 Area and volume foundations
matching base and height
In the shown triangle, the base is 12 cm and a 7 cm segment meets it at a right angle. Identify the base and its corresponding height.
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Base 12 cm and height 7 cm
The pattern behind it: Area and volume foundations
Choose the matching base and perpendicular height, or count equal cube layers before multiplying dimensions.
In this one. A triangle height must be perpendicular to the chosen base. A sloping side is not automatically the height.
How to spot it
Look for shapes drawn on a dotted or squared grid, sharing a side or a vertex, with names like ABCD and ABE. Words like "grid", "dots" or "squares" alongside a request to compare areas or heights are the giveaway.
Common mistake
Children measure height by eye along the slanted side of a shape instead of counting the straight up-down grid distance from the base to the opposite vertex, which gives the wrong height whenever a side leans.
Try one like it
Standard area of a triangle A triangle has base 8 cm and perpendicular height 5 cm. Find its area.The 33 problem patterns
All 33 patterns, one to a page — the 19 behind Primary 5 and 6 word problems, and the skills the younger years are built on. The bar model, how to spot it in the question, and the mistake children make. A booklet you can print. Free.
A PDF, and a note when new solutions go up.