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Finding the Fourth Proportional to 64.95, 89.63 and 38.72

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Solution

The fourth proportional to 64.95, 89.63 and 38.72 is: 53.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    64.95 : 89.63 = 38.72 : x
  2. Step 2: Convert to fraction form
    64.95/89.63 = 38.72/x
  3. Step 3: Cross multiply
    64.95x = 89.63 × 38.72
  4. Step 4: Simplify right side
    64.95x = 3,469.83
  5. Step 5: Solve for x
    x = 3,469.83/64.95
  6. Step 6: Final answer
    x = 53.42

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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.