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Finding the Fourth Proportional to 666.24, 919.20 and 390.24

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Solution

The fourth proportional to 666.24, 919.20 and 390.24 is: 538.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    666.24 : 919.20 = 390.24 : x
  2. Step 2: Convert to fraction form
    666.24/919.20 = 390.24/x
  3. Step 3: Cross multiply
    666.24x = 919.20 × 390.24
  4. Step 4: Simplify right side
    666.24x = 358,708.61
  5. Step 5: Solve for x
    x = 358,708.61/666.24
  6. Step 6: Final answer
    x = 538.41

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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.