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Finding the Fourth Proportional to 99.70, 137.52 and 86.74

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Solution

The fourth proportional to 99.70, 137.52 and 86.74 is: 119.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    99.70 : 137.52 = 86.74 : x
  2. Step 2: Convert to fraction form
    99.70/137.52 = 86.74/x
  3. Step 3: Cross multiply
    99.70x = 137.52 × 86.74
  4. Step 4: Simplify right side
    99.70x = 11,928.48
  5. Step 5: Solve for x
    x = 11,928.48/99.70
  6. Step 6: Final answer
    x = 119.64

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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.