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Finding the Fourth Proportional to 390.94, 583.35 and 388.66

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Solution

The fourth proportional to 390.94, 583.35 and 388.66 is: 579.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.94 : 583.35 = 388.66 : x
  2. Step 2: Convert to fraction form
    390.94/583.35 = 388.66/x
  3. Step 3: Cross multiply
    390.94x = 583.35 × 388.66
  4. Step 4: Simplify right side
    390.94x = 226,724.81
  5. Step 5: Solve for x
    x = 226,724.81/390.94
  6. Step 6: Final answer
    x = 579.95

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.