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Finding the Fourth Proportional to 280.39, 420.54 and 74.94

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Solution

The fourth proportional to 280.39, 420.54 and 74.94 is: 112.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.39 : 420.54 = 74.94 : x
  2. Step 2: Convert to fraction form
    280.39/420.54 = 74.94/x
  3. Step 3: Cross multiply
    280.39x = 420.54 × 74.94
  4. Step 4: Simplify right side
    280.39x = 31,515.27
  5. Step 5: Solve for x
    x = 31,515.27/280.39
  6. Step 6: Final answer
    x = 112.40

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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.