SME
Grade 6 Math · Geometry
Area of triangles, parallelograms and trapezoids
Use this for “A parallelogram has a base of 8 cm and a height of 5 cm. What is its area?”
Diagram
Area: 40 cm².
Move the yellow triangle to the other side: a rectangle 8 by 5.
Leaning the shape keeps the base, the height and the area.
This is an example. Type your own values to start a new problem.
A (cm²)
=
b (cm)
×
h (cm)
Formulas
A
=
b
×
h
(area
=
base
×
height)
40 = 8 × 5
Assumptions
•
The height meets the base at a square corner: it is not the slanted side.
•
Cut a triangle off one end and move it to the other: the parallelogram becomes a rectangle.
•
Any side can be the base, with the height that meets it.
Step-by-step
WE KNOW
b = 8 cm (base), h = 5 cm (height)
FIND
area (A)
Step 1 · Find area (A)
Use A = b × h (area = base × height)
Put the numbers in and multiply: the rectangle it makes.
A
=
8
×
5
A
=
40
cm²
Check
Put the numbers back in. Both sides should match.
40 = 8 × 5 ✓
Topic check
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More problem types
Area of triangles
Use this for “A triangle has base 3 and height 7. What is its area?”
Area of trapezoids
Use this for “The bases are 9 and 15, the height 8. Find the area.”
Area of composite figures
Use this for the area of a house shape: a rectangle with a triangle on top.
Which segment is a height?
Use this for “Which segment is a height for this base?”