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Finding the Fourth Proportional to 646.42, 891.93 and 397.78

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Solution

The fourth proportional to 646.42, 891.93 and 397.78 is: 548.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    646.42 : 891.93 = 397.78 : x
  2. Step 2: Convert to fraction form
    646.42/891.93 = 397.78/x
  3. Step 3: Cross multiply
    646.42x = 891.93 × 397.78
  4. Step 4: Simplify right side
    646.42x = 354,791.92
  5. Step 5: Solve for x
    x = 354,791.92/646.42
  6. Step 6: Final answer
    x = 548.86

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.