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Finding the Fourth Proportional to 280.64, 387.30 and 156.31

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Solution

The fourth proportional to 280.64, 387.30 and 156.31 is: 215.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.64 : 387.30 = 156.31 : x
  2. Step 2: Convert to fraction form
    280.64/387.30 = 156.31/x
  3. Step 3: Cross multiply
    280.64x = 387.30 × 156.31
  4. Step 4: Simplify right side
    280.64x = 60,538.86
  5. Step 5: Solve for x
    x = 60,538.86/280.64
  6. Step 6: Final answer
    x = 215.72

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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.