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Finding the Fourth Proportional to 70.40, 97.15 and 39.31

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Solution

The fourth proportional to 70.40, 97.15 and 39.31 is: 54.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    70.40 : 97.15 = 39.31 : x
  2. Step 2: Convert to fraction form
    70.40/97.15 = 39.31/x
  3. Step 3: Cross multiply
    70.40x = 97.15 × 39.31
  4. Step 4: Simplify right side
    70.40x = 3,818.77
  5. Step 5: Solve for x
    x = 3,818.77/70.40
  6. Step 6: Final answer
    x = 54.24

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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.