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Finding the Fourth Proportional to 420.88, 580.80 and 280.84

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Solution

The fourth proportional to 420.88, 580.80 and 280.84 is: 387.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.88 : 580.80 = 280.84 : x
  2. Step 2: Convert to fraction form
    420.88/580.80 = 280.84/x
  3. Step 3: Cross multiply
    420.88x = 580.80 × 280.84
  4. Step 4: Simplify right side
    420.88x = 163,111.87
  5. Step 5: Solve for x
    x = 163,111.87/420.88
  6. Step 6: Final answer
    x = 387.55

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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.