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Finding the Fourth Proportional to 1,012.88, 1,397.16 and 639.56

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Solution

The fourth proportional to 1,012.88, 1,397.16 and 639.56 is: 882.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,012.88 : 1,397.16 = 639.56 : x
  2. Step 2: Convert to fraction form
    1,012.88/1,397.16 = 639.56/x
  3. Step 3: Cross multiply
    1,012.88x = 1,397.16 × 639.56
  4. Step 4: Simplify right side
    1,012.88x = 893,567.65
  5. Step 5: Solve for x
    x = 893,567.65/1,012.88
  6. Step 6: Final answer
    x = 882.20

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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.