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Finding the Fourth Proportional to 280.80, 420.96 and 256.80

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Solution

The fourth proportional to 280.80, 420.96 and 256.80 is: 384.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.80 : 420.96 = 256.80 : x
  2. Step 2: Convert to fraction form
    280.80/420.96 = 256.80/x
  3. Step 3: Cross multiply
    280.80x = 420.96 × 256.80
  4. Step 4: Simplify right side
    280.80x = 108,102.53
  5. Step 5: Solve for x
    x = 108,102.53/280.80
  6. Step 6: Final answer
    x = 384.98

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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.