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Finding the Fourth Proportional to 518.78, 715.80 and 309.03

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Solution

The fourth proportional to 518.78, 715.80 and 309.03 is: 426.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    518.78 : 715.80 = 309.03 : x
  2. Step 2: Convert to fraction form
    518.78/715.80 = 309.03/x
  3. Step 3: Cross multiply
    518.78x = 715.80 × 309.03
  4. Step 4: Simplify right side
    518.78x = 221,203.67
  5. Step 5: Solve for x
    x = 221,203.67/518.78
  6. Step 6: Final answer
    x = 426.40

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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.