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Finding the Fourth Proportional to 153.12, 210.78 and 138.36

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Solution

The fourth proportional to 153.12, 210.78 and 138.36 is: 190.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    153.12 : 210.78 = 138.36 : x
  2. Step 2: Convert to fraction form
    153.12/210.78 = 138.36/x
  3. Step 3: Cross multiply
    153.12x = 210.78 × 138.36
  4. Step 4: Simplify right side
    153.12x = 29,163.52
  5. Step 5: Solve for x
    x = 29,163.52/153.12
  6. Step 6: Final answer
    x = 190.46

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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.