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Finding the Fourth Proportional to 390.98, 585.43 and 287.48

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Solution

The fourth proportional to 390.98, 585.43 and 287.48 is: 430.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.98 : 585.43 = 287.48 : x
  2. Step 2: Convert to fraction form
    390.98/585.43 = 287.48/x
  3. Step 3: Cross multiply
    390.98x = 585.43 × 287.48
  4. Step 4: Simplify right side
    390.98x = 168,300.16
  5. Step 5: Solve for x
    x = 168,300.16/390.98
  6. Step 6: Final answer
    x = 430.45

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.