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Finding the Fourth Proportional to 842.80, 1,264.20 and 431.36

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Solution

The fourth proportional to 842.80, 1,264.20 and 431.36 is: 647.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    842.80 : 1,264.20 = 431.36 : x
  2. Step 2: Convert to fraction form
    842.80/1,264.20 = 431.36/x
  3. Step 3: Cross multiply
    842.80x = 1,264.20 × 431.36
  4. Step 4: Simplify right side
    842.80x = 545,325.31
  5. Step 5: Solve for x
    x = 545,325.31/842.80
  6. Step 6: Final answer
    x = 647.04

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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.