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Finding the Fourth Proportional to 1,137.12, 1,569.18 and 639.72

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Solution

The fourth proportional to 1,137.12, 1,569.18 and 639.72 is: 882.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,137.12 : 1,569.18 = 639.72 : x
  2. Step 2: Convert to fraction form
    1,137.12/1,569.18 = 639.72/x
  3. Step 3: Cross multiply
    1,137.12x = 1,569.18 × 639.72
  4. Step 4: Simplify right side
    1,137.12x = 1,003,827.98
  5. Step 5: Solve for x
    x = 1,003,827.98/1,137.12
  6. Step 6: Final answer
    x = 882.78

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.