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Finding the Fourth Proportional to 853, 1,279.80 and 420.46

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Solution

The fourth proportional to 853, 1,279.80 and 420.46 is: 630.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    853 : 1,279.80 = 420.46 : x
  2. Step 2: Convert to fraction form
    853/1,279.80 = 420.46/x
  3. Step 3: Cross multiply
    853x = 1,279.80 × 420.46
  4. Step 4: Simplify right side
    853x = 538,104.71
  5. Step 5: Solve for x
    x = 538,104.71/853
  6. Step 6: Final answer
    x = 630.84

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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.