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Finding the Fourth Proportional to 153.09, 211.61 and 128.93

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Solution

The fourth proportional to 153.09, 211.61 and 128.93 is: 178.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    153.09 : 211.61 = 128.93 : x
  2. Step 2: Convert to fraction form
    153.09/211.61 = 128.93/x
  3. Step 3: Cross multiply
    153.09x = 211.61 × 128.93
  4. Step 4: Simplify right side
    153.09x = 27,282.14
  5. Step 5: Solve for x
    x = 27,282.14/153.09
  6. Step 6: Final answer
    x = 178.21

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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.