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Finding the Fourth Proportional to 780.82, 1,170.66 and 415.78

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Solution

The fourth proportional to 780.82, 1,170.66 and 415.78 is: 623.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.82 : 1,170.66 = 415.78 : x
  2. Step 2: Convert to fraction form
    780.82/1,170.66 = 415.78/x
  3. Step 3: Cross multiply
    780.82x = 1,170.66 × 415.78
  4. Step 4: Simplify right side
    780.82x = 486,737.01
  5. Step 5: Solve for x
    x = 486,737.01/780.82
  6. Step 6: Final answer
    x = 623.37

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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.