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Finding the Fourth Proportional to 151.30, 208.78 and 84.90

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Solution

The fourth proportional to 151.30, 208.78 and 84.90 is: 117.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    151.30 : 208.78 = 84.90 : x
  2. Step 2: Convert to fraction form
    151.30/208.78 = 84.90/x
  3. Step 3: Cross multiply
    151.30x = 208.78 × 84.90
  4. Step 4: Simplify right side
    151.30x = 17,725.21
  5. Step 5: Solve for x
    x = 17,725.21/151.30
  6. Step 6: Final answer
    x = 117.15

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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.