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Finding the Fourth Proportional to 208.90, 287.89 and 156.35

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Solution

The fourth proportional to 208.90, 287.89 and 156.35 is: 215.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    208.90 : 287.89 = 156.35 : x
  2. Step 2: Convert to fraction form
    208.90/287.89 = 156.35/x
  3. Step 3: Cross multiply
    208.90x = 287.89 × 156.35
  4. Step 4: Simplify right side
    208.90x = 45,011.60
  5. Step 5: Solve for x
    x = 45,011.60/208.90
  6. Step 6: Final answer
    x = 215.47

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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.