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Finding the Fourth Proportional to 231.95, 320.09 and 128.45

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Solution

The fourth proportional to 231.95, 320.09 and 128.45 is: 177.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    231.95 : 320.09 = 128.45 : x
  2. Step 2: Convert to fraction form
    231.95/320.09 = 128.45/x
  3. Step 3: Cross multiply
    231.95x = 320.09 × 128.45
  4. Step 4: Simplify right side
    231.95x = 41,113.32
  5. Step 5: Solve for x
    x = 41,113.32/231.95
  6. Step 6: Final answer
    x = 177.25

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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.