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Finding the Fourth Proportional to 189.76, 284.64 and 128.74

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Solution

The fourth proportional to 189.76, 284.64 and 128.74 is: 193.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    189.76 : 284.64 = 128.74 : x
  2. Step 2: Convert to fraction form
    189.76/284.64 = 128.74/x
  3. Step 3: Cross multiply
    189.76x = 284.64 × 128.74
  4. Step 4: Simplify right side
    189.76x = 36,643.36
  5. Step 5: Solve for x
    x = 36,643.36/189.76
  6. Step 6: Final answer
    x = 193.11

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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.