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Finding the Fourth Proportional to 261.83, 392.78 and 139.93

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Solution

The fourth proportional to 261.83, 392.78 and 139.93 is: 209.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    261.83 : 392.78 = 139.93 : x
  2. Step 2: Convert to fraction form
    261.83/392.78 = 139.93/x
  3. Step 3: Cross multiply
    261.83x = 392.78 × 139.93
  4. Step 4: Simplify right side
    261.83x = 54,961.07
  5. Step 5: Solve for x
    x = 54,961.07/261.83
  6. Step 6: Final answer
    x = 209.91

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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.