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Finding the Fourth Proportional to 919.20, 1,386.08 and 818.40

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Solution

The fourth proportional to 919.20, 1,386.08 and 818.40 is: 1,234.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    919.20 : 1,386.08 = 818.40 : x
  2. Step 2: Convert to fraction form
    919.20/1,386.08 = 818.40/x
  3. Step 3: Cross multiply
    919.20x = 1,386.08 × 818.40
  4. Step 4: Simplify right side
    919.20x = 1,134,367.87
  5. Step 5: Solve for x
    x = 1,134,367.87/919.20
  6. Step 6: Final answer
    x = 1,234.08

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.