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Finding the Fourth Proportional to 64.40, 89.00 and 55.13

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Solution

The fourth proportional to 64.40, 89.00 and 55.13 is: 76.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    64.40 : 89.00 = 55.13 : x
  2. Step 2: Convert to fraction form
    64.40/89.00 = 55.13/x
  3. Step 3: Cross multiply
    64.40x = 89.00 × 55.13
  4. Step 4: Simplify right side
    64.40x = 4,906.56
  5. Step 5: Solve for x
    x = 4,906.56/64.40
  6. Step 6: Final answer
    x = 76.19

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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.