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Finding the Fourth Proportional to 809.99, 1,214.60 and 439.21

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Solution

The fourth proportional to 809.99, 1,214.60 and 439.21 is: 658.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    809.99 : 1,214.60 = 439.21 : x
  2. Step 2: Convert to fraction form
    809.99/1,214.60 = 439.21/x
  3. Step 3: Cross multiply
    809.99x = 1,214.60 × 439.21
  4. Step 4: Simplify right side
    809.99x = 533,465.44
  5. Step 5: Solve for x
    x = 533,465.44/809.99
  6. Step 6: Final answer
    x = 658.61

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Double scale
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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.