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Finding the Fourth Proportional to 280.50, 420.59 and 85.44

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Solution

The fourth proportional to 280.50, 420.59 and 85.44 is: 128.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.50 : 420.59 = 85.44 : x
  2. Step 2: Convert to fraction form
    280.50/420.59 = 85.44/x
  3. Step 3: Cross multiply
    280.50x = 420.59 × 85.44
  4. Step 4: Simplify right side
    280.50x = 35,934.63
  5. Step 5: Solve for x
    x = 35,934.63/280.50
  6. Step 6: Final answer
    x = 128.11

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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.