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Finding the Fourth Proportional to 891.17, 1,336.20 and 647.90

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Solution

The fourth proportional to 891.17, 1,336.20 and 647.90 is: 971.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    891.17 : 1,336.20 = 647.90 : x
  2. Step 2: Convert to fraction form
    891.17/1,336.20 = 647.90/x
  3. Step 3: Cross multiply
    891.17x = 1,336.20 × 647.90
  4. Step 4: Simplify right side
    891.17x = 865,723.98
  5. Step 5: Solve for x
    x = 865,723.98/891.17
  6. Step 6: Final answer
    x = 971.45

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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.