Interactive study guide — Reveal Math Unit 5 · Standard 6.G
Find the area of a parallelogram using its base and perpendicular height.
A parallelogram has two pairs of parallel sides. To find the area, multiply the base by the height.
Formula: A = b × h
The height must be perpendicular to the base — not the slanted side. Think of it as the straight-up distance between the base and the opposite side.
A parallelogram has a base of 12 cm and a height of 7 cm. What is the area?
Which measurement must be perpendicular to the base when finding area of a parallelogram?
A parallelogram has an area of 54 sq in and a base of 9 in. What is the height?
A triangle is half of a parallelogram, so its area formula uses one-half.
Two identical triangles can always be arranged to form a parallelogram. That's why the area of a triangle is half the area of the related parallelogram.
Formula: A = ½ × b × h
The height is still the perpendicular distance from the base to the opposite vertex.
A triangle has a base of 14 cm and a height of 8 cm. What is the area?
Why is the area formula for a triangle ½ × b × h?
A triangle has an area of 24 sq ft and a base of 8 ft. What is the height?
Use the trapezoid formula and break composite figures into simpler shapes.
A trapezoid has exactly one pair of parallel sides called bases (b₁ and b₂).
Formula: A = ½(b₁ + b₂) × h
Add the two bases, multiply by the height, then take half.
A composite figure is made up of two or more simple shapes. Break it apart, find each area, then add them together.
A trapezoid has bases of 6 cm and 10 cm and a height of 4 cm. What is the area?
To find the area of a composite figure, you should:
A trapezoid has bases of 5 in and 9 in and a height of 6 in. What is the area?
Unfold 3D shapes into nets and find surface area by adding the areas of all faces.
A net is a 2D pattern that folds into a 3D shape. Each face of the solid becomes a flat shape in the net.
Surface area (SA) is the total area of all the faces of a 3D figure.
A rectangular prism has 6 faces (3 pairs of identical rectangles).
Formula: SA = 2(lw + lh + wh)
A rectangular prism is 2 × 3 × 6. What is the surface area?
How many faces does a rectangular prism have?
A cube has edges of 5 cm. What is its surface area?
Find the volume of rectangular prisms, including those with fractional edge lengths and composite 3D figures.
Volume measures the space inside a 3D figure, in cubic units.
Formulas: V = l × w × h or V = B × h (where B is the area of the base)
The same formula works with fractions. Multiply carefully.
Break composite solids into separate rectangular prisms, find each volume, then add them together.
A rectangular prism is 5 × 8 × 3. What is the volume?
A rectangular prism has a base area of 20 sq cm and a height of 7 cm. What is the volume?
A rectangular prism is ½ × 4 × 6. What is the volume?
Tap a card to reveal the definition.