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Finding the Fourth Proportional to 280.70, 420.90 and 118.40

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Solution

The fourth proportional to 280.70, 420.90 and 118.40 is: 177.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.70 : 420.90 = 118.40 : x
  2. Step 2: Convert to fraction form
    280.70/420.90 = 118.40/x
  3. Step 3: Cross multiply
    280.70x = 420.90 × 118.40
  4. Step 4: Simplify right side
    280.70x = 49,834.56
  5. Step 5: Solve for x
    x = 49,834.56/280.70
  6. Step 6: Final answer
    x = 177.54

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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.