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Finding the Fourth Proportional to 1,187.75, 1,639.07 and 663.79

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Solution

The fourth proportional to 1,187.75, 1,639.07 and 663.79 is: 916.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,187.75 : 1,639.07 = 663.79 : x
  2. Step 2: Convert to fraction form
    1,187.75/1,639.07 = 663.79/x
  3. Step 3: Cross multiply
    1,187.75x = 1,639.07 × 663.79
  4. Step 4: Simplify right side
    1,187.75x = 1,087,986.76
  5. Step 5: Solve for x
    x = 1,087,986.76/1,187.75
  6. Step 6: Final answer
    x = 916.01

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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.