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Finding the Fourth Proportional to 666.40, 919.12 and 578.72

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Solution

The fourth proportional to 666.40, 919.12 and 578.72 is: 798.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    666.40 : 919.12 = 578.72 : x
  2. Step 2: Convert to fraction form
    666.40/919.12 = 578.72/x
  3. Step 3: Cross multiply
    666.40x = 919.12 × 578.72
  4. Step 4: Simplify right side
    666.40x = 531,913.13
  5. Step 5: Solve for x
    x = 531,913.13/666.40
  6. Step 6: Final answer
    x = 798.19

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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.