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Finding the Fourth Proportional to 209.47, 314.30 and 87.81

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Solution

The fourth proportional to 209.47, 314.30 and 87.81 is: 131.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.47 : 314.30 = 87.81 : x
  2. Step 2: Convert to fraction form
    209.47/314.30 = 87.81/x
  3. Step 3: Cross multiply
    209.47x = 314.30 × 87.81
  4. Step 4: Simplify right side
    209.47x = 27,598.68
  5. Step 5: Solve for x
    x = 27,598.68/209.47
  6. Step 6: Final answer
    x = 131.75

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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.