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Finding the Fourth Proportional to 1,137.10, 1,569.20 and 639.74

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Solution

The fourth proportional to 1,137.10, 1,569.20 and 639.74 is: 882.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,137.10 : 1,569.20 = 639.74 : x
  2. Step 2: Convert to fraction form
    1,137.10/1,569.20 = 639.74/x
  3. Step 3: Cross multiply
    1,137.10x = 1,569.20 × 639.74
  4. Step 4: Simplify right side
    1,137.10x = 1,003,880.01
  5. Step 5: Solve for x
    x = 1,003,880.01/1,137.10
  6. Step 6: Final answer
    x = 882.84

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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.