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Finding the Fourth Proportional to 854, 1,280.94 and 421

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Solution

The fourth proportional to 854, 1,280.94 and 421 is: 631.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    854 : 1,280.94 = 421 : x
  2. Step 2: Convert to fraction form
    854/1,280.94 = 421/x
  3. Step 3: Cross multiply
    854x = 1,280.94 × 421
  4. Step 4: Simplify right side
    854x = 539,275.74
  5. Step 5: Solve for x
    x = 539,275.74/854
  6. Step 6: Final answer
    x = 631.47

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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.