What students learn
Complementary angles add to 90°; supplementary angles add to 180°. A shot at a wall is a supplementary pair (the path and the wall make a straight line); a straight shot into open green is a complementary pair (a right angle with the aim line as one side). Students solve for the angle that completes the pair. Because the answer controls the shot, precision matters: an answer that's 10° off sends the ball 10° off.
How the game works
- Golf Gamer (easy): wall angles start at multiples of 10°, then 5°, then any whole number. Straight-shot angles can be any whole number from the start.
- Hole-In-One Hero (hard): adds a countdown clock, and on the back nine some angles are given as expressions like (2x + 10)° with x provided, so students substitute before solving. Running out of time counts as a miss.
- Putting Green: free practice with no holes and no limit.
Students aim first: they drag from the ball (or use the arrow keys) to set the direction and power. The question then appears right where the shot will happen, as a diagram: the known angle in gold and the missing one marked “?”, with a white dotted line showing the ball's path. The answer launches the ball.
- Right answer: the ball follows the dotted line, bounces off the wall like a mirror, and the diagram fills in the answer in green. The green line traces the path in and stops at the wall.
- Wrong answer: the ball leaves the wall at the angle the student typed. Their number is drawn as a red wedge next to the gold angle: too small leaves a gray “?” gap before the wall, too big spills past it. A card at the top adds the two angles (for example “50° + 110° = 160°, not 180°”) without giving away the answer. The ball rolls a little slower so students can watch it, and the cup is covered for that stroke.
- Then a retry: once the ball stops, a short explanation of the rule appears (again without the answer), and the same question is asked again from the same spot with a hint: “Supplementary angles always add up to 180°” (or 90° for complementary). A second miss adds the equation with a blank, like 180° − 50° = ?.
Worked examples
Supplementary bank shot (aiming at a wall): the ball's path and the wall make a straight line, and the shown angle is 35°.
35 + ? = 180 ? = 145°
Complementary straight shot (aiming at open green): the aim line is one side of a right angle, and the shown angle is 38°.
38 + ? = 90 ? = 52°
Hole-In-One Hero: the wall angle is (2x + 10)° with x = 25, and the pair is supplementary.
2(25) + 10 = 60° 180 - 60 = 120°
Common mistakes
Using the wrong total (90 instead of 180, or the other way round). The red wedge leaves a huge gap or spills far past the wall, and the sum card shows the total is off by 90°. The retry hint names the right total.
Subtraction slips with non-round angles like 90 − 37. Later holes use any whole number, so students can't rely on round numbers.
Forgetting to evaluate the expression first in Hero mode. Students solve with 2x + 10 as if it were the angle. Have them write the angle's value before they subtract.
Ways to use it in class
- Printables. A free worksheet with an answer key and a two-to-a-page exit ticket match this game, ready to print or save as a PDF.
- One round, then reflect. After nine holes, students write down which hole they missed and why.
- Predict first. Before hitting, students say whether the ball will bank off the wall or roll straight.
- Pairs. One student solves, the other checks the arithmetic before the putt.
- Exit ticket. "An angle is 47°. What is its complement? Its supplement?"
Discussion questions
- Can an angle have a complement if it's bigger than 90°? A supplement?
- Why does a ball leave a wall at the same angle it hit it?
- If your answer was too small, where did the gray gap appear? What would fill it?
- Why does a too-big answer spill past the wall?
Real-world connections
A golf ball, a billiard ball, a laser and a sound wave all leave a wall at the same angle they arrive. Complementary and supplementary angles also guide roof framing, carpentry, and any layout with corners.
Standards
CCSS.MATH.CONTENT.7.G.B.5Use facts about supplementary, complementary, vertical, and adjacent angles in a multi-step problem to write and solve simple equations for an unknown angle in a figure.
Access and privacy
No accounts, no data collected. Each round is a new random course. Plays with a mouse, touch, or the keyboard.