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Finding the Fourth Proportional to 1,187.97, 1,639.35 and 690.81

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Solution

The fourth proportional to 1,187.97, 1,639.35 and 690.81 is: 953.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,187.97 : 1,639.35 = 690.81 : x
  2. Step 2: Convert to fraction form
    1,187.97/1,639.35 = 690.81/x
  3. Step 3: Cross multiply
    1,187.97x = 1,639.35 × 690.81
  4. Step 4: Simplify right side
    1,187.97x = 1,132,479.37
  5. Step 5: Solve for x
    x = 1,132,479.37/1,187.97
  6. Step 6: Final answer
    x = 953.29

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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.