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Finding the Fourth Proportional to 66.47, 91.53 and 61.81

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Solution

The fourth proportional to 66.47, 91.53 and 61.81 is: 85.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.47 : 91.53 = 61.81 : x
  2. Step 2: Convert to fraction form
    66.47/91.53 = 61.81/x
  3. Step 3: Cross multiply
    66.47x = 91.53 × 61.81
  4. Step 4: Simplify right side
    66.47x = 5,657.76
  5. Step 5: Solve for x
    x = 5,657.76/66.47
  6. Step 6: Final answer
    x = 85.12

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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.