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Finding the Fourth Proportional to 390.81, 585.65 and 208.35

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Solution

The fourth proportional to 390.81, 585.65 and 208.35 is: 312.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.81 : 585.65 = 208.35 : x
  2. Step 2: Convert to fraction form
    390.81/585.65 = 208.35/x
  3. Step 3: Cross multiply
    390.81x = 585.65 × 208.35
  4. Step 4: Simplify right side
    390.81x = 122,019.14
  5. Step 5: Solve for x
    x = 122,019.14/390.81
  6. Step 6: Final answer
    x = 312.22

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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.