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Finding the Fourth Proportional to 390.85, 539.63 and 317.32

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Solution

The fourth proportional to 390.85, 539.63 and 317.32 is: 438.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.85 : 539.63 = 317.32 : x
  2. Step 2: Convert to fraction form
    390.85/539.63 = 317.32/x
  3. Step 3: Cross multiply
    390.85x = 539.63 × 317.32
  4. Step 4: Simplify right side
    390.85x = 171,235.39
  5. Step 5: Solve for x
    x = 171,235.39/390.85
  6. Step 6: Final answer
    x = 438.11

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.