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Finding the Fourth Proportional to 807.31, 1,211.57 and 320.40

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Solution

The fourth proportional to 807.31, 1,211.57 and 320.40 is: 480.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    807.31 : 1,211.57 = 320.40 : x
  2. Step 2: Convert to fraction form
    807.31/1,211.57 = 320.40/x
  3. Step 3: Cross multiply
    807.31x = 1,211.57 × 320.40
  4. Step 4: Simplify right side
    807.31x = 388,187.83
  5. Step 5: Solve for x
    x = 388,187.83/807.31
  6. Step 6: Final answer
    x = 480.84

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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.