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Finding the Fourth Proportional to 819.64, 1,228.18 and 515

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Solution

The fourth proportional to 819.64, 1,228.18 and 515 is: 771.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    819.64 : 1,228.18 = 515 : x
  2. Step 2: Convert to fraction form
    819.64/1,228.18 = 515/x
  3. Step 3: Cross multiply
    819.64x = 1,228.18 × 515
  4. Step 4: Simplify right side
    819.64x = 632,512.70
  5. Step 5: Solve for x
    x = 632,512.70/819.64
  6. Step 6: Final answer
    x = 771.70

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.