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Finding the Fourth Proportional to 102.60, 153.36 and 81

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Solution

The fourth proportional to 102.60, 153.36 and 81 is: 121.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.60 : 153.36 = 81 : x
  2. Step 2: Convert to fraction form
    102.60/153.36 = 81/x
  3. Step 3: Cross multiply
    102.60x = 153.36 × 81
  4. Step 4: Simplify right side
    102.60x = 12,422.16
  5. Step 5: Solve for x
    x = 12,422.16/102.60
  6. Step 6: Final answer
    x = 121.07

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.