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Finding the Fourth Proportional to 78.38, 108.20 and 55.08

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Solution

The fourth proportional to 78.38, 108.20 and 55.08 is: 76.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.38 : 108.20 = 55.08 : x
  2. Step 2: Convert to fraction form
    78.38/108.20 = 55.08/x
  3. Step 3: Cross multiply
    78.38x = 108.20 × 55.08
  4. Step 4: Simplify right side
    78.38x = 5,959.38
  5. Step 5: Solve for x
    x = 5,959.38/78.38
  6. Step 6: Final answer
    x = 76.04

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.