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Finding the Fourth Proportional to 128.40, 191.44 and 124.80

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Solution

The fourth proportional to 128.40, 191.44 and 124.80 is: 186.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.40 : 191.44 = 124.80 : x
  2. Step 2: Convert to fraction form
    128.40/191.44 = 124.80/x
  3. Step 3: Cross multiply
    128.40x = 191.44 × 124.80
  4. Step 4: Simplify right side
    128.40x = 23,891.71
  5. Step 5: Solve for x
    x = 23,891.71/128.40
  6. Step 6: Final answer
    x = 186.07

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.