Learn and practice the area of triangles, parallelograms, trapezoids, rhombuses, and composite figures. This build also uses the ideas from your lesson slides: decomposing a stop sign into triangles, finding the area of the Ohio Burgee flag, and solving a regular polygon tile-budget challenge.
Use the simple area steps below. Keep your eyes on the base, the height, and the formula that matches the shape. For composite figures, break the shape apart or put it together.
Notice: a regular polygon can be broken into equal triangles. Wonder: when should I add areas, and when should I subtract them?
Check that you can match the shape and formula before you begin the practice tabs.
A shape has diagonals that cross inside the shape. Which formula matches best?
Use A = 1/2 bh. Multiply the base and height, then take half.
A triangle has base 12 cm and height 9 cm. Fill in each step.
A triangle has area 36 in² and base 9 in. What is the height?
Click to create more triangle problems. You can check each answer and generate a fresh set anytime.
Use A = bh. Do not use the slanted side unless it is shown as the height.
A parallelogram has base 14 m and height 7 m.
A parallelogram has base 11 ft, height 6 ft, and slanted side 8 ft. Use the right measurements.
Use A = ((b₁ + b₂) ÷ 2)h. Follow the order: add the bases → divide by 2 → multiply by the height.
A trapezoid has bases 10 yd and 14 yd and height 6 yd.
A trapezoid has area 54 cm², one base 8 cm, the other base 10 cm, and unknown height.
Use A = 1/2 d₁d₂. Multiply the diagonals, then take half.
A rhombus has diagonals 10 in and 14 in.
A rhombus has area 48 cm² and one diagonal 8 cm. Find the other diagonal.
These are based on the lesson-slide ideas: a regular octagon stop sign, the Ohio Burgee flag, and a regular decagon gazebo floor.
A regular octagon is decomposed into 8 congruent triangles. Each triangle has base 14.9 in and height 18 in.
Compose the flag into a trapezoid with a triangular cut-out. Use bases 8 ft and 5 ft, height 13 ft, and cut-out triangle dimensions 5 ft by 3 ft.
A decagon with equal sides can be decomposed into 10 congruent triangles. Each triangle has base 3.75 ft and height 5.75 ft. Tiles cost $2.89 per square foot.
These mix decomposition and composition strategies. The first few generated problems may include measurement reminders, but later ones require students to read all measurements directly from the visual.
The area of polygons can be found by decomposing them into triangles or quadrilaterals, or by composing them into rectangles or trapezoids. In this mission, the challenge increases as measurement lists gradually disappear and students must rely on the diagrams.
Battle through 3 phases. Correct answers damage the boss, wrong answers hurt you, and power-ups help you survive the hardest round.
Students move from guided practice to visual-only challenge problems, then into the boss battle.
Use these tools to quickly capture student progress from the browser.
Earn badges as you complete each world and clear the final battle.