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Finding the Fourth Proportional to 809.49, 1,213.71 and 398.90

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Solution

The fourth proportional to 809.49, 1,213.71 and 398.90 is: 598.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    809.49 : 1,213.71 = 398.90 : x
  2. Step 2: Convert to fraction form
    809.49/1,213.71 = 398.90/x
  3. Step 3: Cross multiply
    809.49x = 1,213.71 × 398.90
  4. Step 4: Simplify right side
    809.49x = 484,148.17
  5. Step 5: Solve for x
    x = 484,148.17/809.49
  6. Step 6: Final answer
    x = 598.09

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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.