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Finding the Fourth Proportional to 838.78, 1,157.13 and 641.95

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Solution

The fourth proportional to 838.78, 1,157.13 and 641.95 is: 885.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    838.78 : 1,157.13 = 641.95 : x
  2. Step 2: Convert to fraction form
    838.78/1,157.13 = 641.95/x
  3. Step 3: Cross multiply
    838.78x = 1,157.13 × 641.95
  4. Step 4: Simplify right side
    838.78x = 742,816.39
  5. Step 5: Solve for x
    x = 742,816.39/838.78
  6. Step 6: Final answer
    x = 885.59

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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.