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Finding the Fourth Proportional to 390.88, 538 and 303.20

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Solution

The fourth proportional to 390.88, 538 and 303.20 is: 417.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.88 : 538 = 303.20 : x
  2. Step 2: Convert to fraction form
    390.88/538 = 303.20/x
  3. Step 3: Cross multiply
    390.88x = 538 × 303.20
  4. Step 4: Simplify right side
    390.88x = 163,121.60
  5. Step 5: Solve for x
    x = 163,121.60/390.88
  6. Step 6: Final answer
    x = 417.32

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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.