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Finding the Fourth Proportional to 66.31, 91.29 and 55.21

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Solution

The fourth proportional to 66.31, 91.29 and 55.21 is: 76.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.31 : 91.29 = 55.21 : x
  2. Step 2: Convert to fraction form
    66.31/91.29 = 55.21/x
  3. Step 3: Cross multiply
    66.31x = 91.29 × 55.21
  4. Step 4: Simplify right side
    66.31x = 5,040.12
  5. Step 5: Solve for x
    x = 5,040.12/66.31
  6. Step 6: Final answer
    x = 76.01

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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.