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Finding the Fourth Proportional to 64.87, 89.51 and 40.31

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Solution

The fourth proportional to 64.87, 89.51 and 40.31 is: 55.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    64.87 : 89.51 = 40.31 : x
  2. Step 2: Convert to fraction form
    64.87/89.51 = 40.31/x
  3. Step 3: Cross multiply
    64.87x = 89.51 × 40.31
  4. Step 4: Simplify right side
    64.87x = 3,608.17
  5. Step 5: Solve for x
    x = 3,608.17/64.87
  6. Step 6: Final answer
    x = 55.62

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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.