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Finding the Fourth Proportional to 214.30, 321.45 and 128.23

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Solution

The fourth proportional to 214.30, 321.45 and 128.23 is: 192.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    214.30 : 321.45 = 128.23 : x
  2. Step 2: Convert to fraction form
    214.30/321.45 = 128.23/x
  3. Step 3: Cross multiply
    214.30x = 321.45 × 128.23
  4. Step 4: Simplify right side
    214.30x = 41,219.53
  5. Step 5: Solve for x
    x = 41,219.53/214.30
  6. Step 6: Final answer
    x = 192.35

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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.