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Finding the Fourth Proportional to 108.61, 149.80 and 71.72

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Solution

The fourth proportional to 108.61, 149.80 and 71.72 is: 98.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    108.61 : 149.80 = 71.72 : x
  2. Step 2: Convert to fraction form
    108.61/149.80 = 71.72/x
  3. Step 3: Cross multiply
    108.61x = 149.80 × 71.72
  4. Step 4: Simplify right side
    108.61x = 10,743.42
  5. Step 5: Solve for x
    x = 10,743.42/108.61
  6. Step 6: Final answer
    x = 98.92

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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.