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Finding the Fourth Proportional to 66.51, 91.13 and 65.61

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Solution

The fourth proportional to 66.51, 91.13 and 65.61 is: 89.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.51 : 91.13 = 65.61 : x
  2. Step 2: Convert to fraction form
    66.51/91.13 = 65.61/x
  3. Step 3: Cross multiply
    66.51x = 91.13 × 65.61
  4. Step 4: Simplify right side
    66.51x = 5,978.71
  5. Step 5: Solve for x
    x = 5,978.71/66.51
  6. Step 6: Final answer
    x = 89.89

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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.