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Finding the Fourth Proportional to 209, 313.50 and 87.18

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Solution

The fourth proportional to 209, 313.50 and 87.18 is: 130.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    209 : 313.50 = 87.18 : x
  2. Step 2: Convert to fraction form
    209/313.50 = 87.18/x
  3. Step 3: Cross multiply
    209x = 313.50 × 87.18
  4. Step 4: Simplify right side
    209x = 27,330.93
  5. Step 5: Solve for x
    x = 27,330.93/209
  6. Step 6: Final answer
    x = 130.77

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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.