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Finding the Fourth Proportional to 99.30, 137.12 and 66.70

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Solution

The fourth proportional to 99.30, 137.12 and 66.70 is: 92.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    99.30 : 137.12 = 66.70 : x
  2. Step 2: Convert to fraction form
    99.30/137.12 = 66.70/x
  3. Step 3: Cross multiply
    99.30x = 137.12 × 66.70
  4. Step 4: Simplify right side
    99.30x = 9,145.23
  5. Step 5: Solve for x
    x = 9,145.23/99.30
  6. Step 6: Final answer
    x = 92.10

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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.