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Finding the Fourth Proportional to 120.91, 181.30 and 72.15

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Solution

The fourth proportional to 120.91, 181.30 and 72.15 is: 108.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.91 : 181.30 = 72.15 : x
  2. Step 2: Convert to fraction form
    120.91/181.30 = 72.15/x
  3. Step 3: Cross multiply
    120.91x = 181.30 × 72.15
  4. Step 4: Simplify right side
    120.91x = 13,081.40
  5. Step 5: Solve for x
    x = 13,081.40/120.91
  6. Step 6: Final answer
    x = 108.19

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.