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Finding the Fourth Proportional to 390.93, 538.85 and 320.87

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Solution

The fourth proportional to 390.93, 538.85 and 320.87 is: 442.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.93 : 538.85 = 320.87 : x
  2. Step 2: Convert to fraction form
    390.93/538.85 = 320.87/x
  3. Step 3: Cross multiply
    390.93x = 538.85 × 320.87
  4. Step 4: Simplify right side
    390.93x = 172,900.80
  5. Step 5: Solve for x
    x = 172,900.80/390.93
  6. Step 6: Final answer
    x = 442.28

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.