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Finding the Fourth Proportional to 1,639.40, 2,456.10 and 771.80

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Solution

The fourth proportional to 1,639.40, 2,456.10 and 771.80 is: 1,156.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,639.40 : 2,456.10 = 771.80 : x
  2. Step 2: Convert to fraction form
    1,639.40/2,456.10 = 771.80/x
  3. Step 3: Cross multiply
    1,639.40x = 2,456.10 × 771.80
  4. Step 4: Simplify right side
    1,639.40x = 1,895,617.98
  5. Step 5: Solve for x
    x = 1,895,617.98/1,639.40
  6. Step 6: Final answer
    x = 1,156.29

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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.