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Finding the Fourth Proportional to 818.78, 1,129.89 and 469.45

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Solution

The fourth proportional to 818.78, 1,129.89 and 469.45 is: 647.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    818.78 : 1,129.89 = 469.45 : x
  2. Step 2: Convert to fraction form
    818.78/1,129.89 = 469.45/x
  3. Step 3: Cross multiply
    818.78x = 1,129.89 × 469.45
  4. Step 4: Simplify right side
    818.78x = 530,421.21
  5. Step 5: Solve for x
    x = 530,421.21/818.78
  6. Step 6: Final answer
    x = 647.82

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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.