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Finding the Fourth Proportional to 66.38, 99.70 and 57.72

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Solution

The fourth proportional to 66.38, 99.70 and 57.72 is: 86.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.38 : 99.70 = 57.72 : x
  2. Step 2: Convert to fraction form
    66.38/99.70 = 57.72/x
  3. Step 3: Cross multiply
    66.38x = 99.70 × 57.72
  4. Step 4: Simplify right side
    66.38x = 5,754.68
  5. Step 5: Solve for x
    x = 5,754.68/66.38
  6. Step 6: Final answer
    x = 86.69

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.