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Finding the Fourth Proportional to 280.40, 419.70 and 258.80

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Solution

The fourth proportional to 280.40, 419.70 and 258.80 is: 387.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.40 : 419.70 = 258.80 : x
  2. Step 2: Convert to fraction form
    280.40/419.70 = 258.80/x
  3. Step 3: Cross multiply
    280.40x = 419.70 × 258.80
  4. Step 4: Simplify right side
    280.40x = 108,618.36
  5. Step 5: Solve for x
    x = 108,618.36/280.40
  6. Step 6: Final answer
    x = 387.37

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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.