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Finding the Fourth Proportional to 66.86, 91.66 and 65.64

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Solution

The fourth proportional to 66.86, 91.66 and 65.64 is: 89.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.86 : 91.66 = 65.64 : x
  2. Step 2: Convert to fraction form
    66.86/91.66 = 65.64/x
  3. Step 3: Cross multiply
    66.86x = 91.66 × 65.64
  4. Step 4: Simplify right side
    66.86x = 6,016.40
  5. Step 5: Solve for x
    x = 6,016.40/66.86
  6. Step 6: Final answer
    x = 89.99

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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.