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Finding the Fourth Proportional to 102.30, 141.21 and 87.72

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Solution

The fourth proportional to 102.30, 141.21 and 87.72 is: 121.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.30 : 141.21 = 87.72 : x
  2. Step 2: Convert to fraction form
    102.30/141.21 = 87.72/x
  3. Step 3: Cross multiply
    102.30x = 141.21 × 87.72
  4. Step 4: Simplify right side
    102.30x = 12,386.94
  5. Step 5: Solve for x
    x = 12,386.94/102.30
  6. Step 6: Final answer
    x = 121.08

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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.