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Finding the Fourth Proportional to 817.78, 1,223.70 and 509.80

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Solution

The fourth proportional to 817.78, 1,223.70 and 509.80 is: 762.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    817.78 : 1,223.70 = 509.80 : x
  2. Step 2: Convert to fraction form
    817.78/1,223.70 = 509.80/x
  3. Step 3: Cross multiply
    817.78x = 1,223.70 × 509.80
  4. Step 4: Simplify right side
    817.78x = 623,842.26
  5. Step 5: Solve for x
    x = 623,842.26/817.78
  6. Step 6: Final answer
    x = 762.85

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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.