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Finding the Fourth Proportional to 390.28, 583.21 and 318.20

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Solution

The fourth proportional to 390.28, 583.21 and 318.20 is: 475.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.28 : 583.21 = 318.20 : x
  2. Step 2: Convert to fraction form
    390.28/583.21 = 318.20/x
  3. Step 3: Cross multiply
    390.28x = 583.21 × 318.20
  4. Step 4: Simplify right side
    390.28x = 185,577.42
  5. Step 5: Solve for x
    x = 185,577.42/390.28
  6. Step 6: Final answer
    x = 475.50

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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.