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Finding the Fourth Proportional to 390.62, 531.83 and 389.40

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Solution

The fourth proportional to 390.62, 531.83 and 389.40 is: 530.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.62 : 531.83 = 389.40 : x
  2. Step 2: Convert to fraction form
    390.62/531.83 = 389.40/x
  3. Step 3: Cross multiply
    390.62x = 531.83 × 389.40
  4. Step 4: Simplify right side
    390.62x = 207,094.60
  5. Step 5: Solve for x
    x = 207,094.60/390.62
  6. Step 6: Final answer
    x = 530.17

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Why These Related Problems?

These problems maintain the same ratio (1.36) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.