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Finding the Fourth Proportional to 99.64, 137.54 and 77.72

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Solution

The fourth proportional to 99.64, 137.54 and 77.72 is: 107.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    99.64 : 137.54 = 77.72 : x
  2. Step 2: Convert to fraction form
    99.64/137.54 = 77.72/x
  3. Step 3: Cross multiply
    99.64x = 137.54 × 77.72
  4. Step 4: Simplify right side
    99.64x = 10,689.61
  5. Step 5: Solve for x
    x = 10,689.61/99.64
  6. Step 6: Final answer
    x = 107.28

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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.