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Finding the Fourth Proportional to 216.79, 299.21 and 128.23

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Solution

The fourth proportional to 216.79, 299.21 and 128.23 is: 176.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    216.79 : 299.21 = 128.23 : x
  2. Step 2: Convert to fraction form
    216.79/299.21 = 128.23/x
  3. Step 3: Cross multiply
    216.79x = 299.21 × 128.23
  4. Step 4: Simplify right side
    216.79x = 38,366.31
  5. Step 5: Solve for x
    x = 38,366.31/216.79
  6. Step 6: Final answer
    x = 176.98

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.