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Finding the Fourth Proportional to 819.43, 1,129.48 and 642.10

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Solution

The fourth proportional to 819.43, 1,129.48 and 642.10 is: 885.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    819.43 : 1,129.48 = 642.10 : x
  2. Step 2: Convert to fraction form
    819.43/1,129.48 = 642.10/x
  3. Step 3: Cross multiply
    819.43x = 1,129.48 × 642.10
  4. Step 4: Simplify right side
    819.43x = 725,239.11
  5. Step 5: Solve for x
    x = 725,239.11/819.43
  6. Step 6: Final answer
    x = 885.05

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1.5x scale

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.