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Finding the Fourth Proportional to 78, 116.80 and 55.12

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Solution

The fourth proportional to 78, 116.80 and 55.12 is: 82.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    78 : 116.80 = 55.12 : x
  2. Step 2: Convert to fraction form
    78/116.80 = 55.12/x
  3. Step 3: Cross multiply
    78x = 116.80 × 55.12
  4. Step 4: Simplify right side
    78x = 6,438.02
  5. Step 5: Solve for x
    x = 6,438.02/78
  6. Step 6: Final answer
    x = 82.54

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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.