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Finding the Fourth Proportional to 780.12, 1,171.09 and 415.62

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Solution

The fourth proportional to 780.12, 1,171.09 and 415.62 is: 623.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.12 : 1,171.09 = 415.62 : x
  2. Step 2: Convert to fraction form
    780.12/1,171.09 = 415.62/x
  3. Step 3: Cross multiply
    780.12x = 1,171.09 × 415.62
  4. Step 4: Simplify right side
    780.12x = 486,728.43
  5. Step 5: Solve for x
    x = 486,728.43/780.12
  6. Step 6: Final answer
    x = 623.91

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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.