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Finding the Fourth Proportional to 64.70, 89.12 and 54.85

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Solution

The fourth proportional to 64.70, 89.12 and 54.85 is: 75.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    64.70 : 89.12 = 54.85 : x
  2. Step 2: Convert to fraction form
    64.70/89.12 = 54.85/x
  3. Step 3: Cross multiply
    64.70x = 89.12 × 54.85
  4. Step 4: Simplify right side
    64.70x = 4,888.23
  5. Step 5: Solve for x
    x = 4,888.23/64.70
  6. Step 6: Final answer
    x = 75.55

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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.