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Finding the Fourth Proportional to 842.19, 1,263.78 and 431.70

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Solution

The fourth proportional to 842.19, 1,263.78 and 431.70 is: 647.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    842.19 : 1,263.78 = 431.70 : x
  2. Step 2: Convert to fraction form
    842.19/1,263.78 = 431.70/x
  3. Step 3: Cross multiply
    842.19x = 1,263.78 × 431.70
  4. Step 4: Simplify right side
    842.19x = 545,573.83
  5. Step 5: Solve for x
    x = 545,573.83/842.19
  6. Step 6: Final answer
    x = 647.80

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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.