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Finding the Fourth Proportional to 280.21, 386.68 and 155.87

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Solution

The fourth proportional to 280.21, 386.68 and 155.87 is: 215.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.21 : 386.68 = 155.87 : x
  2. Step 2: Convert to fraction form
    280.21/386.68 = 155.87/x
  3. Step 3: Cross multiply
    280.21x = 386.68 × 155.87
  4. Step 4: Simplify right side
    280.21x = 60,270.58
  5. Step 5: Solve for x
    x = 60,270.58/280.21
  6. Step 6: Final answer
    x = 215.09

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.