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Finding the Fourth Proportional to 99.81, 137.74 and 61

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Solution

The fourth proportional to 99.81, 137.74 and 61 is: 84.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    99.81 : 137.74 = 61 : x
  2. Step 2: Convert to fraction form
    99.81/137.74 = 61/x
  3. Step 3: Cross multiply
    99.81x = 137.74 × 61
  4. Step 4: Simplify right side
    99.81x = 8,402.29
  5. Step 5: Solve for x
    x = 8,402.29/99.81
  6. Step 6: Final answer
    x = 84.18

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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.