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Finding the Fourth Proportional to 72.30, 108.49 and 31.72

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Solution

The fourth proportional to 72.30, 108.49 and 31.72 is: 47.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.30 : 108.49 = 31.72 : x
  2. Step 2: Convert to fraction form
    72.30/108.49 = 31.72/x
  3. Step 3: Cross multiply
    72.30x = 108.49 × 31.72
  4. Step 4: Simplify right side
    72.30x = 3,441.30
  5. Step 5: Solve for x
    x = 3,441.30/72.30
  6. Step 6: Final answer
    x = 47.60

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.