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Finding the Fourth Proportional to 153.87, 212.30 and 87.47

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Solution

The fourth proportional to 153.87, 212.30 and 87.47 is: 120.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    153.87 : 212.30 = 87.47 : x
  2. Step 2: Convert to fraction form
    153.87/212.30 = 87.47/x
  3. Step 3: Cross multiply
    153.87x = 212.30 × 87.47
  4. Step 4: Simplify right side
    153.87x = 18,568.38
  5. Step 5: Solve for x
    x = 18,568.38/153.87
  6. Step 6: Final answer
    x = 120.68

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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.