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Finding the Fourth Proportional to 655.90, 905.24 and 390.35

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Solution

The fourth proportional to 655.90, 905.24 and 390.35 is: 538.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    655.90 : 905.24 = 390.35 : x
  2. Step 2: Convert to fraction form
    655.90/905.24 = 390.35/x
  3. Step 3: Cross multiply
    655.90x = 905.24 × 390.35
  4. Step 4: Simplify right side
    655.90x = 353,363.67
  5. Step 5: Solve for x
    x = 353,363.67/655.90
  6. Step 6: Final answer
    x = 538.75

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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.