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Finding the Fourth Proportional to 806.72, 1,210.28 and 319.80

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Solution

The fourth proportional to 806.72, 1,210.28 and 319.80 is: 479.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    806.72 : 1,210.28 = 319.80 : x
  2. Step 2: Convert to fraction form
    806.72/1,210.28 = 319.80/x
  3. Step 3: Cross multiply
    806.72x = 1,210.28 × 319.80
  4. Step 4: Simplify right side
    806.72x = 387,047.54
  5. Step 5: Solve for x
    x = 387,047.54/806.72
  6. Step 6: Final answer
    x = 479.78

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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.