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Finding the Fourth Proportional to 90.70, 135.96 and 66.64

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Solution

The fourth proportional to 90.70, 135.96 and 66.64 is: 99.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.70 : 135.96 = 66.64 : x
  2. Step 2: Convert to fraction form
    90.70/135.96 = 66.64/x
  3. Step 3: Cross multiply
    90.70x = 135.96 × 66.64
  4. Step 4: Simplify right side
    90.70x = 9,060.37
  5. Step 5: Solve for x
    x = 9,060.37/90.70
  6. Step 6: Final answer
    x = 99.89

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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.