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Finding the Fourth Proportional to 655.95, 905.12 and 390.51

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Solution

The fourth proportional to 655.95, 905.12 and 390.51 is: 538.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    655.95 : 905.12 = 390.51 : x
  2. Step 2: Convert to fraction form
    655.95/905.12 = 390.51/x
  3. Step 3: Cross multiply
    655.95x = 905.12 × 390.51
  4. Step 4: Simplify right side
    655.95x = 353,456.46
  5. Step 5: Solve for x
    x = 353,456.46/655.95
  6. Step 6: Final answer
    x = 538.85

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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.