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Finding the Fourth Proportional to 779.90, 1,169.31 and 389.34

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Solution

The fourth proportional to 779.90, 1,169.31 and 389.34 is: 583.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    779.90 : 1,169.31 = 389.34 : x
  2. Step 2: Convert to fraction form
    779.90/1,169.31 = 389.34/x
  3. Step 3: Cross multiply
    779.90x = 1,169.31 × 389.34
  4. Step 4: Simplify right side
    779.90x = 455,260.13
  5. Step 5: Solve for x
    x = 455,260.13/779.90
  6. Step 6: Final answer
    x = 583.74

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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.