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Finding the Fourth Proportional to 390.69, 539.06 and 316.89

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Solution

The fourth proportional to 390.69, 539.06 and 316.89 is: 437.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.69 : 539.06 = 316.89 : x
  2. Step 2: Convert to fraction form
    390.69/539.06 = 316.89/x
  3. Step 3: Cross multiply
    390.69x = 539.06 × 316.89
  4. Step 4: Simplify right side
    390.69x = 170,821.14
  5. Step 5: Solve for x
    x = 170,821.14/390.69
  6. Step 6: Final answer
    x = 437.23

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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.