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Finding the Fourth Proportional to 987.83, 1,478.09 and 812.87

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Solution

The fourth proportional to 987.83, 1,478.09 and 812.87 is: 1,216.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    987.83 : 1,478.09 = 812.87 : x
  2. Step 2: Convert to fraction form
    987.83/1,478.09 = 812.87/x
  3. Step 3: Cross multiply
    987.83x = 1,478.09 × 812.87
  4. Step 4: Simplify right side
    987.83x = 1,201,495.02
  5. Step 5: Solve for x
    x = 1,201,495.02/987.83
  6. Step 6: Final answer
    x = 1,216.30

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.