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Finding the Fourth Proportional to 430.70, 646.58 and 428.72

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Solution

The fourth proportional to 430.70, 646.58 and 428.72 is: 643.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    430.70 : 646.58 = 428.72 : x
  2. Step 2: Convert to fraction form
    430.70/646.58 = 428.72/x
  3. Step 3: Cross multiply
    430.70x = 646.58 × 428.72
  4. Step 4: Simplify right side
    430.70x = 277,201.78
  5. Step 5: Solve for x
    x = 277,201.78/430.70
  6. Step 6: Final answer
    x = 643.61

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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.