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Finding the Fourth Proportional to 390.64, 585.54 and 208.15

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Solution

The fourth proportional to 390.64, 585.54 and 208.15 is: 312.00

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.64 : 585.54 = 208.15 : x
  2. Step 2: Convert to fraction form
    390.64/585.54 = 208.15/x
  3. Step 3: Cross multiply
    390.64x = 585.54 × 208.15
  4. Step 4: Simplify right side
    390.64x = 121,880.15
  5. Step 5: Solve for x
    x = 121,880.15/390.64
  6. Step 6: Final answer
    x = 312.00

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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.