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Finding the Fourth Proportional to 390.96, 535.28 and 389.58

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Solution

The fourth proportional to 390.96, 535.28 and 389.58 is: 533.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.96 : 535.28 = 389.58 : x
  2. Step 2: Convert to fraction form
    390.96/535.28 = 389.58/x
  3. Step 3: Cross multiply
    390.96x = 535.28 × 389.58
  4. Step 4: Simplify right side
    390.96x = 208,534.38
  5. Step 5: Solve for x
    x = 208,534.38/390.96
  6. Step 6: Final answer
    x = 533.39

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.