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Finding the Fourth Proportional to 99.80, 137.65 and 66.59

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Solution

The fourth proportional to 99.80, 137.65 and 66.59 is: 91.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    99.80 : 137.65 = 66.59 : x
  2. Step 2: Convert to fraction form
    99.80/137.65 = 66.59/x
  3. Step 3: Cross multiply
    99.80x = 137.65 × 66.59
  4. Step 4: Simplify right side
    99.80x = 9,166.46
  5. Step 5: Solve for x
    x = 9,166.46/99.80
  6. Step 6: Final answer
    x = 91.85

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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.