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Finding the Fourth Proportional to 842.78, 1,264.44 and 430.90

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Solution

The fourth proportional to 842.78, 1,264.44 and 430.90 is: 646.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    842.78 : 1,264.44 = 430.90 : x
  2. Step 2: Convert to fraction form
    842.78/1,264.44 = 430.90/x
  3. Step 3: Cross multiply
    842.78x = 1,264.44 × 430.90
  4. Step 4: Simplify right side
    842.78x = 544,847.20
  5. Step 5: Solve for x
    x = 544,847.20/842.78
  6. Step 6: Final answer
    x = 646.49

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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.