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Finding the Fourth Proportional to 390.86, 539.16 and 317.24

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Solution

The fourth proportional to 390.86, 539.16 and 317.24 is: 437.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.86 : 539.16 = 317.24 : x
  2. Step 2: Convert to fraction form
    390.86/539.16 = 317.24/x
  3. Step 3: Cross multiply
    390.86x = 539.16 × 317.24
  4. Step 4: Simplify right side
    390.86x = 171,043.12
  5. Step 5: Solve for x
    x = 171,043.12/390.86
  6. Step 6: Final answer
    x = 437.61

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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.