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Finding the Fourth Proportional to 518.28, 776.34 and 431.40

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Solution

The fourth proportional to 518.28, 776.34 and 431.40 is: 646.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    518.28 : 776.34 = 431.40 : x
  2. Step 2: Convert to fraction form
    518.28/776.34 = 431.40/x
  3. Step 3: Cross multiply
    518.28x = 776.34 × 431.40
  4. Step 4: Simplify right side
    518.28x = 334,913.08
  5. Step 5: Solve for x
    x = 334,913.08/518.28
  6. Step 6: Final answer
    x = 646.20

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.