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Finding the Fourth Proportional to 71.78, 99.18 and 53.48

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Solution

The fourth proportional to 71.78, 99.18 and 53.48 is: 73.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    71.78 : 99.18 = 53.48 : x
  2. Step 2: Convert to fraction form
    71.78/99.18 = 53.48/x
  3. Step 3: Cross multiply
    71.78x = 99.18 × 53.48
  4. Step 4: Simplify right side
    71.78x = 5,304.39
  5. Step 5: Solve for x
    x = 5,304.39/71.78
  6. Step 6: Final answer
    x = 73.90

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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.