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Finding the Fourth Proportional to 72.56, 108.80 and 31.40

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Solution

The fourth proportional to 72.56, 108.80 and 31.40 is: 47.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.56 : 108.80 = 31.40 : x
  2. Step 2: Convert to fraction form
    72.56/108.80 = 31.40/x
  3. Step 3: Cross multiply
    72.56x = 108.80 × 31.40
  4. Step 4: Simplify right side
    72.56x = 3,416.32
  5. Step 5: Solve for x
    x = 3,416.32/72.56
  6. Step 6: Final answer
    x = 47.08

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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.