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Finding the Fourth Proportional to 280.38, 386.88 and 156.05

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Solution

The fourth proportional to 280.38, 386.88 and 156.05 is: 215.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.38 : 386.88 = 156.05 : x
  2. Step 2: Convert to fraction form
    280.38/386.88 = 156.05/x
  3. Step 3: Cross multiply
    280.38x = 386.88 × 156.05
  4. Step 4: Simplify right side
    280.38x = 60,370.69
  5. Step 5: Solve for x
    x = 60,370.69/280.38
  6. Step 6: Final answer
    x = 215.32

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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.