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Finding the Fourth Proportional to 99.40, 137.10 and 66.64

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Solution

The fourth proportional to 99.40, 137.10 and 66.64 is: 91.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    99.40 : 137.10 = 66.64 : x
  2. Step 2: Convert to fraction form
    99.40/137.10 = 66.64/x
  3. Step 3: Cross multiply
    99.40x = 137.10 × 66.64
  4. Step 4: Simplify right side
    99.40x = 9,136.34
  5. Step 5: Solve for x
    x = 9,136.34/99.40
  6. Step 6: Final answer
    x = 91.91

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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.