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Finding the Fourth Proportional to 215.58, 323.30 and 128.72

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Solution

The fourth proportional to 215.58, 323.30 and 128.72 is: 193.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    215.58 : 323.30 = 128.72 : x
  2. Step 2: Convert to fraction form
    215.58/323.30 = 128.72/x
  3. Step 3: Cross multiply
    215.58x = 323.30 × 128.72
  4. Step 4: Simplify right side
    215.58x = 41,615.18
  5. Step 5: Solve for x
    x = 41,615.18/215.58
  6. Step 6: Final answer
    x = 193.04

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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.