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Finding the Fourth Proportional to 782.89, 1,078.93 and 642.19

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Solution

The fourth proportional to 782.89, 1,078.93 and 642.19 is: 885.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    782.89 : 1,078.93 = 642.19 : x
  2. Step 2: Convert to fraction form
    782.89/1,078.93 = 642.19/x
  3. Step 3: Cross multiply
    782.89x = 1,078.93 × 642.19
  4. Step 4: Simplify right side
    782.89x = 692,881.40
  5. Step 5: Solve for x
    x = 692,881.40/782.89
  6. Step 6: Final answer
    x = 885.03

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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.