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Finding the Fourth Proportional to 292.19, 438.31 and 86.78

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Solution

The fourth proportional to 292.19, 438.31 and 86.78 is: 130.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    292.19 : 438.31 = 86.78 : x
  2. Step 2: Convert to fraction form
    292.19/438.31 = 86.78/x
  3. Step 3: Cross multiply
    292.19x = 438.31 × 86.78
  4. Step 4: Simplify right side
    292.19x = 38,036.54
  5. Step 5: Solve for x
    x = 38,036.54/292.19
  6. Step 6: Final answer
    x = 130.18

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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.