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Finding the Fourth Proportional to 807.68, 1,210.79 and 320.40

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Solution

The fourth proportional to 807.68, 1,210.79 and 320.40 is: 480.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    807.68 : 1,210.79 = 320.40 : x
  2. Step 2: Convert to fraction form
    807.68/1,210.79 = 320.40/x
  3. Step 3: Cross multiply
    807.68x = 1,210.79 × 320.40
  4. Step 4: Simplify right side
    807.68x = 387,937.12
  5. Step 5: Solve for x
    x = 387,937.12/807.68
  6. Step 6: Final answer
    x = 480.31

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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.