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Finding the Fourth Proportional to 518.10, 780.71 and 428.79

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Solution

The fourth proportional to 518.10, 780.71 and 428.79 is: 646.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    518.10 : 780.71 = 428.79 : x
  2. Step 2: Convert to fraction form
    518.10/780.71 = 428.79/x
  3. Step 3: Cross multiply
    518.10x = 780.71 × 428.79
  4. Step 4: Simplify right side
    518.10x = 334,758.50
  5. Step 5: Solve for x
    x = 334,758.50/518.10
  6. Step 6: Final answer
    x = 646.13

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.