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Finding the Fourth Proportional to 153.90, 212.38 and 87.51

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Solution

The fourth proportional to 153.90, 212.38 and 87.51 is: 120.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    153.90 : 212.38 = 87.51 : x
  2. Step 2: Convert to fraction form
    153.90/212.38 = 87.51/x
  3. Step 3: Cross multiply
    153.90x = 212.38 × 87.51
  4. Step 4: Simplify right side
    153.90x = 18,584.72
  5. Step 5: Solve for x
    x = 18,584.72/153.90
  6. Step 6: Final answer
    x = 120.76

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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.