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Finding the Fourth Proportional to 782.30, 1,172.10 and 417.80

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Solution

The fourth proportional to 782.30, 1,172.10 and 417.80 is: 625.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    782.30 : 1,172.10 = 417.80 : x
  2. Step 2: Convert to fraction form
    782.30/1,172.10 = 417.80/x
  3. Step 3: Cross multiply
    782.30x = 1,172.10 × 417.80
  4. Step 4: Simplify right side
    782.30x = 489,703.38
  5. Step 5: Solve for x
    x = 489,703.38/782.30
  6. Step 6: Final answer
    x = 625.98

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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.