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Finding the Fourth Proportional to 189.80, 284.70 and 128.60

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Solution

The fourth proportional to 189.80, 284.70 and 128.60 is: 192.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    189.80 : 284.70 = 128.60 : x
  2. Step 2: Convert to fraction form
    189.80/284.70 = 128.60/x
  3. Step 3: Cross multiply
    189.80x = 284.70 × 128.60
  4. Step 4: Simplify right side
    189.80x = 36,612.42
  5. Step 5: Solve for x
    x = 36,612.42/189.80
  6. Step 6: Final answer
    x = 192.90

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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.