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Finding the Fourth Proportional to 860.50, 1,187.49 and 640.50

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Solution

The fourth proportional to 860.50, 1,187.49 and 640.50 is: 883.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    860.50 : 1,187.49 = 640.50 : x
  2. Step 2: Convert to fraction form
    860.50/1,187.49 = 640.50/x
  3. Step 3: Cross multiply
    860.50x = 1,187.49 × 640.50
  4. Step 4: Simplify right side
    860.50x = 760,587.35
  5. Step 5: Solve for x
    x = 760,587.35/860.50
  6. Step 6: Final answer
    x = 883.89

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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.