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Finding the Fourth Proportional to 389.90, 538.10 and 257.06

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Solution

The fourth proportional to 389.90, 538.10 and 257.06 is: 354.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    389.90 : 538.10 = 257.06 : x
  2. Step 2: Convert to fraction form
    389.90/538.10 = 257.06/x
  3. Step 3: Cross multiply
    389.90x = 538.10 × 257.06
  4. Step 4: Simplify right side
    389.90x = 138,320.01
  5. Step 5: Solve for x
    x = 138,320.01/389.90
  6. Step 6: Final answer
    x = 354.76

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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.