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Finding the Fourth Proportional to 521.49, 781.95 and 257.90

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Solution

The fourth proportional to 521.49, 781.95 and 257.90 is: 386.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    521.49 : 781.95 = 257.90 : x
  2. Step 2: Convert to fraction form
    521.49/781.95 = 257.90/x
  3. Step 3: Cross multiply
    521.49x = 781.95 × 257.90
  4. Step 4: Simplify right side
    521.49x = 201,666.36
  5. Step 5: Solve for x
    x = 201,666.36/521.49
  6. Step 6: Final answer
    x = 386.71

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.