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Finding the Fourth Proportional to 389.28, 581.72 and 317.20

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Solution

The fourth proportional to 389.28, 581.72 and 317.20 is: 474.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    389.28 : 581.72 = 317.20 : x
  2. Step 2: Convert to fraction form
    389.28/581.72 = 317.20/x
  3. Step 3: Cross multiply
    389.28x = 581.72 × 317.20
  4. Step 4: Simplify right side
    389.28x = 184,521.58
  5. Step 5: Solve for x
    x = 184,521.58/389.28
  6. Step 6: Final answer
    x = 474.01

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.