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Finding the Fourth Proportional to 390.21, 585.31 and 170.76

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Solution

The fourth proportional to 390.21, 585.31 and 170.76 is: 256.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.21 : 585.31 = 170.76 : x
  2. Step 2: Convert to fraction form
    390.21/585.31 = 170.76/x
  3. Step 3: Cross multiply
    390.21x = 585.31 × 170.76
  4. Step 4: Simplify right side
    390.21x = 99,947.54
  5. Step 5: Solve for x
    x = 99,947.54/390.21
  6. Step 6: Final answer
    x = 256.14

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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.