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Finding the Fourth Proportional to 64.78, 89.39 and 40.22

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Solution

The fourth proportional to 64.78, 89.39 and 40.22 is: 55.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    64.78 : 89.39 = 40.22 : x
  2. Step 2: Convert to fraction form
    64.78/89.39 = 40.22/x
  3. Step 3: Cross multiply
    64.78x = 89.39 × 40.22
  4. Step 4: Simplify right side
    64.78x = 3,594.89
  5. Step 5: Solve for x
    x = 3,594.89/64.78
  6. Step 6: Final answer
    x = 55.50

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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.