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Finding the Fourth Proportional to 65.56, 89.90 and 61.78

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Solution

The fourth proportional to 65.56, 89.90 and 61.78 is: 84.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    65.56 : 89.90 = 61.78 : x
  2. Step 2: Convert to fraction form
    65.56/89.90 = 61.78/x
  3. Step 3: Cross multiply
    65.56x = 89.90 × 61.78
  4. Step 4: Simplify right side
    65.56x = 5,554.02
  5. Step 5: Solve for x
    x = 5,554.02/65.56
  6. Step 6: Final answer
    x = 84.72

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.