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Finding the Fourth Proportional to 280.55, 420.84 and 75.12

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Solution

The fourth proportional to 280.55, 420.84 and 75.12 is: 112.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.55 : 420.84 = 75.12 : x
  2. Step 2: Convert to fraction form
    280.55/420.84 = 75.12/x
  3. Step 3: Cross multiply
    280.55x = 420.84 × 75.12
  4. Step 4: Simplify right side
    280.55x = 31,613.50
  5. Step 5: Solve for x
    x = 31,613.50/280.55
  6. Step 6: Final answer
    x = 112.68

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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.