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Finding the Fourth Proportional to 1,685.12, 2,528 and 819.20

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Solution

The fourth proportional to 1,685.12, 2,528 and 819.20 is: 1,228.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,685.12 : 2,528 = 819.20 : x
  2. Step 2: Convert to fraction form
    1,685.12/2,528 = 819.20/x
  3. Step 3: Cross multiply
    1,685.12x = 2,528 × 819.20
  4. Step 4: Simplify right side
    1,685.12x = 2,070,937.60
  5. Step 5: Solve for x
    x = 2,070,937.60/1,685.12
  6. Step 6: Final answer
    x = 1,228.96

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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.