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Finding the Fourth Proportional to 64.91, 89.55 and 40.31

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Solution

The fourth proportional to 64.91, 89.55 and 40.31 is: 55.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    64.91 : 89.55 = 40.31 : x
  2. Step 2: Convert to fraction form
    64.91/89.55 = 40.31/x
  3. Step 3: Cross multiply
    64.91x = 89.55 × 40.31
  4. Step 4: Simplify right side
    64.91x = 3,609.31
  5. Step 5: Solve for x
    x = 3,609.31/64.91
  6. Step 6: Final answer
    x = 55.61

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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.