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Finding the Fourth Proportional to 805.20, 1,207.80 and 724.20

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Solution

The fourth proportional to 805.20, 1,207.80 and 724.20 is: 1,086.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    805.20 : 1,207.80 = 724.20 : x
  2. Step 2: Convert to fraction form
    805.20/1,207.80 = 724.20/x
  3. Step 3: Cross multiply
    805.20x = 1,207.80 × 724.20
  4. Step 4: Simplify right side
    805.20x = 874,688.76
  5. Step 5: Solve for x
    x = 874,688.76/805.20
  6. Step 6: Final answer
    x = 1,086.30

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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.