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Finding the Fourth Proportional to 66.80, 91.58 and 64.64

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Solution

The fourth proportional to 66.80, 91.58 and 64.64 is: 88.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.80 : 91.58 = 64.64 : x
  2. Step 2: Convert to fraction form
    66.80/91.58 = 64.64/x
  3. Step 3: Cross multiply
    66.80x = 91.58 × 64.64
  4. Step 4: Simplify right side
    66.80x = 5,919.73
  5. Step 5: Solve for x
    x = 5,919.73/66.80
  6. Step 6: Final answer
    x = 88.62

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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.