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Finding the Fourth Proportional to 151.40, 208.90 and 85.90

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Solution

The fourth proportional to 151.40, 208.90 and 85.90 is: 118.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    151.40 : 208.90 = 85.90 : x
  2. Step 2: Convert to fraction form
    151.40/208.90 = 85.90/x
  3. Step 3: Cross multiply
    151.40x = 208.90 × 85.90
  4. Step 4: Simplify right side
    151.40x = 17,944.51
  5. Step 5: Solve for x
    x = 17,944.51/151.40
  6. Step 6: Final answer
    x = 118.52

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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.