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Finding the Fourth Proportional to 261.61, 392.34 and 78.95

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Solution

The fourth proportional to 261.61, 392.34 and 78.95 is: 118.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    261.61 : 392.34 = 78.95 : x
  2. Step 2: Convert to fraction form
    261.61/392.34 = 78.95/x
  3. Step 3: Cross multiply
    261.61x = 392.34 × 78.95
  4. Step 4: Simplify right side
    261.61x = 30,975.24
  5. Step 5: Solve for x
    x = 30,975.24/261.61
  6. Step 6: Final answer
    x = 118.40

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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.