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Finding the Fourth Proportional to 390.68, 585.52 and 208.16

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Solution

The fourth proportional to 390.68, 585.52 and 208.16 is: 311.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.68 : 585.52 = 208.16 : x
  2. Step 2: Convert to fraction form
    390.68/585.52 = 208.16/x
  3. Step 3: Cross multiply
    390.68x = 585.52 × 208.16
  4. Step 4: Simplify right side
    390.68x = 121,881.84
  5. Step 5: Solve for x
    x = 121,881.84/390.68
  6. Step 6: Final answer
    x = 311.97

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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.