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Finding the Fourth Proportional to 1,297.98, 1,946.31 and 639.90

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Solution

The fourth proportional to 1,297.98, 1,946.31 and 639.90 is: 959.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,297.98 : 1,946.31 = 639.90 : x
  2. Step 2: Convert to fraction form
    1,297.98/1,946.31 = 639.90/x
  3. Step 3: Cross multiply
    1,297.98x = 1,946.31 × 639.90
  4. Step 4: Simplify right side
    1,297.98x = 1,245,443.77
  5. Step 5: Solve for x
    x = 1,245,443.77/1,297.98
  6. Step 6: Final answer
    x = 959.52

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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.