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Finding the Fourth Proportional to 209.40, 314.07 and 87.65

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Solution

The fourth proportional to 209.40, 314.07 and 87.65 is: 131.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.40 : 314.07 = 87.65 : x
  2. Step 2: Convert to fraction form
    209.40/314.07 = 87.65/x
  3. Step 3: Cross multiply
    209.40x = 314.07 × 87.65
  4. Step 4: Simplify right side
    209.40x = 27,526.67
  5. Step 5: Solve for x
    x = 27,526.67/209.40
  6. Step 6: Final answer
    x = 131.45

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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.