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Finding the Fourth Proportional to 108.15, 148.40 and 100.86

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Solution

The fourth proportional to 108.15, 148.40 and 100.86 is: 138.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    108.15 : 148.40 = 100.86 : x
  2. Step 2: Convert to fraction form
    108.15/148.40 = 100.86/x
  3. Step 3: Cross multiply
    108.15x = 148.40 × 100.86
  4. Step 4: Simplify right side
    108.15x = 14,967.12
  5. Step 5: Solve for x
    x = 14,967.12/108.15
  6. Step 6: Final answer
    x = 138.39

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.