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Finding the Fourth Proportional to 871.78, 1,203.42 and 623.20

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Solution

The fourth proportional to 871.78, 1,203.42 and 623.20 is: 860.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    871.78 : 1,203.42 = 623.20 : x
  2. Step 2: Convert to fraction form
    871.78/1,203.42 = 623.20/x
  3. Step 3: Cross multiply
    871.78x = 1,203.42 × 623.20
  4. Step 4: Simplify right side
    871.78x = 749,971.34
  5. Step 5: Solve for x
    x = 749,971.34/871.78
  6. Step 6: Final answer
    x = 860.28

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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.