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Finding the Fourth Proportional to 199.79, 275.72 and 128.87

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Solution

The fourth proportional to 199.79, 275.72 and 128.87 is: 177.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    199.79 : 275.72 = 128.87 : x
  2. Step 2: Convert to fraction form
    199.79/275.72 = 128.87/x
  3. Step 3: Cross multiply
    199.79x = 275.72 × 128.87
  4. Step 4: Simplify right side
    199.79x = 35,530.98
  5. Step 5: Solve for x
    x = 35,530.98/199.79
  6. Step 6: Final answer
    x = 177.84

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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.