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Finding the Fourth Proportional to 784.20, 1,173.78 and 418.08

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Solution

The fourth proportional to 784.20, 1,173.78 and 418.08 is: 625.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    784.20 : 1,173.78 = 418.08 : x
  2. Step 2: Convert to fraction form
    784.20/1,173.78 = 418.08/x
  3. Step 3: Cross multiply
    784.20x = 1,173.78 × 418.08
  4. Step 4: Simplify right side
    784.20x = 490,733.94
  5. Step 5: Solve for x
    x = 490,733.94/784.20
  6. Step 6: Final answer
    x = 625.78

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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.