# Robo-Math How Far?

```Robo-Math: How Far?
The Distance a Robot Travels in One Rotation of the Motor
= The Circumference of the Wheel
Circumference (of the Wheel) = Diameter (of the Wheel) x ∏
Figuring a unit rate: Distance for one rotation (knobby wheels)
Do this: 1) Figure the circumference of the wheel (use cm)
diameter of wheel
x
x
∏
= circumference
_______cm
3.14 = ________
2) This gives a unit rate (for knobby wheels)
# of cm moved per 1 rotation
3) Unit rate for knobby wheels is: (notice the format)
______cm / 1 rotation
(per)
Robo-Math: How Far?
The Distance a Robot Travels in One Rotation of the Motor
= The Circumference of the Wheel
Circumference (of the Wheel) = Diameter (of the Wheel) x ∏
3 Work Questions:
A) How Far will the Robot travel with 720⁰ of rotation?
(using knobby wheels)
B)How many Rotations will it take for the Robot to go 50cm?
(using skinny wheels)
C) How many Rotations will it take for the Robot to go 25in?
(using wide wheels)
Robo-Math
Question A: How Far will the Robot travel with 720⁰ of
rotation? (knobby wheels)
Step 1) How many degrees are in one rotation?
___?___degrees / 1 rotation
Step 2) Set up a proportion to find the number of rotations in 720⁰.
____?⁰__ =
_720_ ⁰
1 rotation
n rotations
Solve by using scale factor (relationship between ratios)
Step 3) Distance travelled = Unit rate (# of cm / 1 rotation), times
the number of rotations
Distance travelled = _______ cm X __n__
Step 4) Demonstrate:
- Write a program to move 720 degrees
- Measure & draw predicted distance line, place Lego Dude on line
Robo-Math
Question B: How many Rotations will it take for the Robot to
go 50cm? (skinny wheels)
Step 1) Now find the unit rate for the wheel using cm.
diameter of wheel x ∏ = circumference
_______cm
x 3.14 = ________
Unit rate for the skinny wheel is: (notice the format)
______cm / 1 rotation
Step 2) Set up a proportion using this unit rate
__ ?__ cm
=
__50__ cm
1 rotation
n
rotations
Solve by using scale factor (relationship between ratios)
Step 3) Write a program using your robo-math for Move block
duration
Step 4) Demonstrate:
- Place Lego Dude on 50 cm line
Robo-Math
Question C: How many Rotations will it take for the Robot to
go 25in? (wide wheels)
Step 1) Now find the unit rate for the wide wheels using inches.
diameter of wheel x ∏ = circumference
_______in.
x 3.14 = ________
Unit rate for the wide wheel is: (notice the format)
______in. / 1 rotation
Step 2) Set up a proportion using this unit rate.
__(?)_in.
=
__25 in.__
1 rotation
n rotations
Solve by using scale factor (relationship between ratios)
Step 3) Write a program using your robo-math for Move block duration
Step 4) Demonstrate: - Place Lego Dude on 25 in. line
- Run program
```

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