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Finding the Fourth Proportional to 987.70, 1,363.61 and 656.81

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Solution

The fourth proportional to 987.70, 1,363.61 and 656.81 is: 906.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    987.70 : 1,363.61 = 656.81 : x
  2. Step 2: Convert to fraction form
    987.70/1,363.61 = 656.81/x
  3. Step 3: Cross multiply
    987.70x = 1,363.61 × 656.81
  4. Step 4: Simplify right side
    987.70x = 895,629.40
  5. Step 5: Solve for x
    x = 895,629.40/987.70
  6. Step 6: Final answer
    x = 906.79

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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.