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Finding the Fourth Proportional to 818.47, 1,128.71 and 631.66

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Solution

The fourth proportional to 818.47, 1,128.71 and 631.66 is: 871.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    818.47 : 1,128.71 = 631.66 : x
  2. Step 2: Convert to fraction form
    818.47/1,128.71 = 631.66/x
  3. Step 3: Cross multiply
    818.47x = 1,128.71 × 631.66
  4. Step 4: Simplify right side
    818.47x = 712,960.96
  5. Step 5: Solve for x
    x = 712,960.96/818.47
  6. Step 6: Final answer
    x = 871.09

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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.