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Finding the Fourth Proportional to 780.61, 1,169.90 and 317.85

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Solution

The fourth proportional to 780.61, 1,169.90 and 317.85 is: 476.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.61 : 1,169.90 = 317.85 : x
  2. Step 2: Convert to fraction form
    780.61/1,169.90 = 317.85/x
  3. Step 3: Cross multiply
    780.61x = 1,169.90 × 317.85
  4. Step 4: Simplify right side
    780.61x = 371,852.72
  5. Step 5: Solve for x
    x = 371,852.72/780.61
  6. Step 6: Final answer
    x = 476.36

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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.