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Finding the Fourth Proportional to 819.60, 1,231.80 and 805.20

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Solution

The fourth proportional to 819.60, 1,231.80 and 805.20 is: 1,210.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    819.60 : 1,231.80 = 805.20 : x
  2. Step 2: Convert to fraction form
    819.60/1,231.80 = 805.20/x
  3. Step 3: Cross multiply
    819.60x = 1,231.80 × 805.20
  4. Step 4: Simplify right side
    819.60x = 991,845.36
  5. Step 5: Solve for x
    x = 991,845.36/819.60
  6. Step 6: Final answer
    x = 1,210.16

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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.