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Finding the Fourth Proportional to 216.36, 324.40 and 129.72

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Solution

The fourth proportional to 216.36, 324.40 and 129.72 is: 194.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    216.36 : 324.40 = 129.72 : x
  2. Step 2: Convert to fraction form
    216.36/324.40 = 129.72/x
  3. Step 3: Cross multiply
    216.36x = 324.40 × 129.72
  4. Step 4: Simplify right side
    216.36x = 42,081.17
  5. Step 5: Solve for x
    x = 42,081.17/216.36
  6. Step 6: Final answer
    x = 194.50

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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.