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Finding the Fourth Proportional to 861.17, 1,290.75 and 422.63

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Solution

The fourth proportional to 861.17, 1,290.75 and 422.63 is: 633.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    861.17 : 1,290.75 = 422.63 : x
  2. Step 2: Convert to fraction form
    861.17/1,290.75 = 422.63/x
  3. Step 3: Cross multiply
    861.17x = 1,290.75 × 422.63
  4. Step 4: Simplify right side
    861.17x = 545,509.67
  5. Step 5: Solve for x
    x = 545,509.67/861.17
  6. Step 6: Final answer
    x = 633.45

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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.