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Finding the Fourth Proportional to 208.81, 313.21 and 87

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Solution

The fourth proportional to 208.81, 313.21 and 87 is: 130.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    208.81 : 313.21 = 87 : x
  2. Step 2: Convert to fraction form
    208.81/313.21 = 87/x
  3. Step 3: Cross multiply
    208.81x = 313.21 × 87
  4. Step 4: Simplify right side
    208.81x = 27,249.27
  5. Step 5: Solve for x
    x = 27,249.27/208.81
  6. Step 6: Final answer
    x = 130.50

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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.