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Finding the Fourth Proportional to 430.76, 646.12 and 142.20

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Solution

The fourth proportional to 430.76, 646.12 and 142.20 is: 213.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    430.76 : 646.12 = 142.20 : x
  2. Step 2: Convert to fraction form
    430.76/646.12 = 142.20/x
  3. Step 3: Cross multiply
    430.76x = 646.12 × 142.20
  4. Step 4: Simplify right side
    430.76x = 91,878.26
  5. Step 5: Solve for x
    x = 91,878.26/430.76
  6. Step 6: Final answer
    x = 213.29

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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.