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Finding the Fourth Proportional to 65.87, 90.85 and 64.86

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Solution

The fourth proportional to 65.87, 90.85 and 64.86 is: 89.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    65.87 : 90.85 = 64.86 : x
  2. Step 2: Convert to fraction form
    65.87/90.85 = 64.86/x
  3. Step 3: Cross multiply
    65.87x = 90.85 × 64.86
  4. Step 4: Simplify right side
    65.87x = 5,891.75
  5. Step 5: Solve for x
    x = 5,891.75/65.87
  6. Step 6: Final answer
    x = 89.45

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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.