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Finding the Fourth Proportional to 42.79, 64.10 and 31.25

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Solution

The fourth proportional to 42.79, 64.10 and 31.25 is: 46.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    42.79 : 64.10 = 31.25 : x
  2. Step 2: Convert to fraction form
    42.79/64.10 = 31.25/x
  3. Step 3: Cross multiply
    42.79x = 64.10 × 31.25
  4. Step 4: Simplify right side
    42.79x = 2,002.80
  5. Step 5: Solve for x
    x = 2,002.80/42.79
  6. Step 6: Final answer
    x = 46.81

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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.