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Finding the Fourth Proportional to 219.64, 328.91 and 128.06

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Solution

The fourth proportional to 219.64, 328.91 and 128.06 is: 191.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    219.64 : 328.91 = 128.06 : x
  2. Step 2: Convert to fraction form
    219.64/328.91 = 128.06/x
  3. Step 3: Cross multiply
    219.64x = 328.91 × 128.06
  4. Step 4: Simplify right side
    219.64x = 42,118.89
  5. Step 5: Solve for x
    x = 42,118.89/219.64
  6. Step 6: Final answer
    x = 191.77

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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.