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Finding the Fourth Proportional to 779.80, 1,169.70 and 415.30

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Solution

The fourth proportional to 779.80, 1,169.70 and 415.30 is: 622.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    779.80 : 1,169.70 = 415.30 : x
  2. Step 2: Convert to fraction form
    779.80/1,169.70 = 415.30/x
  3. Step 3: Cross multiply
    779.80x = 1,169.70 × 415.30
  4. Step 4: Simplify right side
    779.80x = 485,776.41
  5. Step 5: Solve for x
    x = 485,776.41/779.80
  6. Step 6: Final answer
    x = 622.95

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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.