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Finding the Fourth Proportional to 120.72, 181.08 and 78

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Solution

The fourth proportional to 120.72, 181.08 and 78 is: 117.00

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.72 : 181.08 = 78 : x
  2. Step 2: Convert to fraction form
    120.72/181.08 = 78/x
  3. Step 3: Cross multiply
    120.72x = 181.08 × 78
  4. Step 4: Simplify right side
    120.72x = 14,124.24
  5. Step 5: Solve for x
    x = 14,124.24/120.72
  6. Step 6: Final answer
    x = 117.00

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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.