Students use a triple beam balance to determine mass values and color the corresponding sections according to a color key.

To solve the problem, we need to determine the mass indicated by each triple beam balance and then match it with the corresponding color based on the provided key. Let's go through each balance step by step.

Step 1: Understand the Triple Beam Balance

A triple beam balance has three sliding weights (beams) that are used to measure mass:
1. Rider on the far right: This is the smallest weight and typically measures in grams.
2. Middle beam: This measures in tens of grams.
3. Leftmost beam: This measures in hundreds of grams.

The total mass is the sum of the values from all three beams.

Step 2: Solve Each Triple Beam Balance

We will analyze each balance one by one.

#### Balance 4-1:
- Hundreds beam: 0
- Tens beam: 0
- Grams beam: 6.5 grams
- Total mass: \( 0 + 0 + 6.5 = 6.5 \) grams
- Color: ORANGE

#### Balance 4-2:
- Hundreds beam: 0
- Tens beam: 0
- Grams beam: 9.5 grams
- Total mass: \( 0 + 0 + 9.5 = 9.5 \) grams
- Color: GREEN

#### Balance 4-3:
- Hundreds beam: 0
- Tens beam: 10 grams
- Grams beam: 2.5 grams
- Total mass: \( 0 + 10 + 2.5 = 12.5 \) grams
- Color: BROWN

#### Balance 4-4:
- Hundreds beam: 0
- Tens beam: 70 grams
- Grams beam: 7 grams
- Total mass: \( 0 + 70 + 7 = 77 \) grams
- Color: BLUE

#### Balance 4-5:
- Hundreds beam: 0
- Tens beam: 150 grams
- Grams beam: 2.5 grams
- Total mass: \( 0 + 150 + 2.5 = 152.5 \) grams
- Color: RED

#### Balance 4-6:
- Hundreds beam: 0
- Tens beam: 60 grams
- Grams beam: 0.9 grams
- Total mass: \( 0 + 60 + 0.9 = 60.9 \) grams
- Color: BLACK

#### Balance 4-7:
- Hundreds beam: 0
- Tens beam: 17 grams
- Grams beam: 0 grams
- Total mass: \( 0 + 17 + 0 = 17 \) grams
- Color: GREY

#### Balance 4-8:
- Hundreds beam: 0
- Tens beam: 25 grams
- Grams beam: 0 grams
- Total mass: \( 0 + 25 + 0 = 25 \) grams
- Color: YELLOW

#### Balance 4-9:
- Hundreds beam: 0
- Tens beam: 103 grams
- Grams beam: 0 grams
- Total mass: \( 0 + 103 + 0 = 103 \) grams
- Color: PURPLE

Step 3: Match Colors to the Key

Using the key provided in the image, we can confirm the colors for each mass.

Final Answer:

\[
\boxed{
\begin{array}{ll}
4-1: & \text{ORANGE} \\
4-2: & \text{GREEN} \\
4-3: & \text{BROWN} \\
4-4: & \text{BLUE} \\
4-5: & \text{RED} \\
4-6: & \text{BLACK} \\
4-7: & \text{GREY} \\
4-8: & \text{YELLOW} \\
4-9: & \text{PURPLE} \\
\end{array}
}
\]