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Finding the Fourth Proportional to 261.90, 392.88 and 79.30

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Solution

The fourth proportional to 261.90, 392.88 and 79.30 is: 118.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    261.90 : 392.88 = 79.30 : x
  2. Step 2: Convert to fraction form
    261.90/392.88 = 79.30/x
  3. Step 3: Cross multiply
    261.90x = 392.88 × 79.30
  4. Step 4: Simplify right side
    261.90x = 31,155.38
  5. Step 5: Solve for x
    x = 31,155.38/261.90
  6. Step 6: Final answer
    x = 118.96

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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.