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Finding the Fourth Proportional to 74.18, 102.39 and 71.90

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Solution

The fourth proportional to 74.18, 102.39 and 71.90 is: 99.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    74.18 : 102.39 = 71.90 : x
  2. Step 2: Convert to fraction form
    74.18/102.39 = 71.90/x
  3. Step 3: Cross multiply
    74.18x = 102.39 × 71.90
  4. Step 4: Simplify right side
    74.18x = 7,361.84
  5. Step 5: Solve for x
    x = 7,361.84/74.18
  6. Step 6: Final answer
    x = 99.24

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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.