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Finding the Fourth Proportional to 853.16, 1,280.20 and 420.32

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Solution

The fourth proportional to 853.16, 1,280.20 and 420.32 is: 630.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    853.16 : 1,280.20 = 420.32 : x
  2. Step 2: Convert to fraction form
    853.16/1,280.20 = 420.32/x
  3. Step 3: Cross multiply
    853.16x = 1,280.20 × 420.32
  4. Step 4: Simplify right side
    853.16x = 538,093.66
  5. Step 5: Solve for x
    x = 538,093.66/853.16
  6. Step 6: Final answer
    x = 630.71

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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.