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Finding the Fourth Proportional to 853.84, 1,280.82 and 420.76

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Solution

The fourth proportional to 853.84, 1,280.82 and 420.76 is: 631.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    853.84 : 1,280.82 = 420.76 : x
  2. Step 2: Convert to fraction form
    853.84/1,280.82 = 420.76/x
  3. Step 3: Cross multiply
    853.84x = 1,280.82 × 420.76
  4. Step 4: Simplify right side
    853.84x = 538,911.42
  5. Step 5: Solve for x
    x = 538,911.42/853.84
  6. Step 6: Final answer
    x = 631.17

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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.