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Finding the Fourth Proportional to 518.40, 715.48 and 393.86

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Solution

The fourth proportional to 518.40, 715.48 and 393.86 is: 543.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    518.40 : 715.48 = 393.86 : x
  2. Step 2: Convert to fraction form
    518.40/715.48 = 393.86/x
  3. Step 3: Cross multiply
    518.40x = 715.48 × 393.86
  4. Step 4: Simplify right side
    518.40x = 281,799.76
  5. Step 5: Solve for x
    x = 281,799.76/518.40
  6. Step 6: Final answer
    x = 543.60

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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.