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Finding the Fourth Proportional to 287.39, 396.58 and 156.40

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Solution

The fourth proportional to 287.39, 396.58 and 156.40 is: 215.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    287.39 : 396.58 = 156.40 : x
  2. Step 2: Convert to fraction form
    287.39/396.58 = 156.40/x
  3. Step 3: Cross multiply
    287.39x = 396.58 × 156.40
  4. Step 4: Simplify right side
    287.39x = 62,023.13
  5. Step 5: Solve for x
    x = 62,023.13/287.39
  6. Step 6: Final answer
    x = 215.82

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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.