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Finding the Fourth Proportional to 70.87, 105.86 and 64.81

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Solution

The fourth proportional to 70.87, 105.86 and 64.81 is: 96.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    70.87 : 105.86 = 64.81 : x
  2. Step 2: Convert to fraction form
    70.87/105.86 = 64.81/x
  3. Step 3: Cross multiply
    70.87x = 105.86 × 64.81
  4. Step 4: Simplify right side
    70.87x = 6,860.79
  5. Step 5: Solve for x
    x = 6,860.79/70.87
  6. Step 6: Final answer
    x = 96.81

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.