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Finding the Fourth Proportional to 70.90, 106.31 and 64.86

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Solution

The fourth proportional to 70.90, 106.31 and 64.86 is: 97.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    70.90 : 106.31 = 64.86 : x
  2. Step 2: Convert to fraction form
    70.90/106.31 = 64.86/x
  3. Step 3: Cross multiply
    70.90x = 106.31 × 64.86
  4. Step 4: Simplify right side
    70.90x = 6,894.54
  5. Step 5: Solve for x
    x = 6,894.54/70.90
  6. Step 6: Final answer
    x = 97.24

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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.