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Finding the Fourth Proportional to 890.79, 1,228.36 and 643.29

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Solution

The fourth proportional to 890.79, 1,228.36 and 643.29 is: 887.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    890.79 : 1,228.36 = 643.29 : x
  2. Step 2: Convert to fraction form
    890.79/1,228.36 = 643.29/x
  3. Step 3: Cross multiply
    890.79x = 1,228.36 × 643.29
  4. Step 4: Simplify right side
    890.79x = 790,191.70
  5. Step 5: Solve for x
    x = 790,191.70/890.79
  6. Step 6: Final answer
    x = 887.07

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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.