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Finding the Fourth Proportional to 261.30, 391.92 and 90.30

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Solution

The fourth proportional to 261.30, 391.92 and 90.30 is: 135.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    261.30 : 391.92 = 90.30 : x
  2. Step 2: Convert to fraction form
    261.30/391.92 = 90.30/x
  3. Step 3: Cross multiply
    261.30x = 391.92 × 90.30
  4. Step 4: Simplify right side
    261.30x = 35,390.38
  5. Step 5: Solve for x
    x = 35,390.38/261.30
  6. Step 6: Final answer
    x = 135.44

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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.