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Finding the Fourth Proportional to 823.20, 1,234.08 and 390.56

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Solution

The fourth proportional to 823.20, 1,234.08 and 390.56 is: 585.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    823.20 : 1,234.08 = 390.56 : x
  2. Step 2: Convert to fraction form
    823.20/1,234.08 = 390.56/x
  3. Step 3: Cross multiply
    823.20x = 1,234.08 × 390.56
  4. Step 4: Simplify right side
    823.20x = 481,982.28
  5. Step 5: Solve for x
    x = 481,982.28/823.20
  6. Step 6: Final answer
    x = 585.50

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Double scale
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1.5x scale

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.