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Finding the Fourth Proportional to 390.33, 538.47 and 307.31

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Solution

The fourth proportional to 390.33, 538.47 and 307.31 is: 423.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.33 : 538.47 = 307.31 : x
  2. Step 2: Convert to fraction form
    390.33/538.47 = 307.31/x
  3. Step 3: Cross multiply
    390.33x = 538.47 × 307.31
  4. Step 4: Simplify right side
    390.33x = 165,474.52
  5. Step 5: Solve for x
    x = 165,474.52/390.33
  6. Step 6: Final answer
    x = 423.93

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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.