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Finding the Fourth Proportional to 188.40, 282.70 and 85.70

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Solution

The fourth proportional to 188.40, 282.70 and 85.70 is: 128.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    188.40 : 282.70 = 85.70 : x
  2. Step 2: Convert to fraction form
    188.40/282.70 = 85.70/x
  3. Step 3: Cross multiply
    188.40x = 282.70 × 85.70
  4. Step 4: Simplify right side
    188.40x = 24,227.39
  5. Step 5: Solve for x
    x = 24,227.39/188.40
  6. Step 6: Final answer
    x = 128.60

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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.