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Finding the Fourth Proportional to 201.78, 302.40 and 86.07

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Solution

The fourth proportional to 201.78, 302.40 and 86.07 is: 128.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    201.78 : 302.40 = 86.07 : x
  2. Step 2: Convert to fraction form
    201.78/302.40 = 86.07/x
  3. Step 3: Cross multiply
    201.78x = 302.40 × 86.07
  4. Step 4: Simplify right side
    201.78x = 26,027.57
  5. Step 5: Solve for x
    x = 26,027.57/201.78
  6. Step 6: Final answer
    x = 128.99

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.