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Finding the Fourth Proportional to 1,407.20, 1,942.40 and 817.92

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Solution

The fourth proportional to 1,407.20, 1,942.40 and 817.92 is: 1,129.00

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,407.20 : 1,942.40 = 817.92 : x
  2. Step 2: Convert to fraction form
    1,407.20/1,942.40 = 817.92/x
  3. Step 3: Cross multiply
    1,407.20x = 1,942.40 × 817.92
  4. Step 4: Simplify right side
    1,407.20x = 1,588,727.81
  5. Step 5: Solve for x
    x = 1,588,727.81/1,407.20
  6. Step 6: Final answer
    x = 1,129.00

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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.