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Finding the Fourth Proportional to 390.70, 585.43 and 253.45

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Solution

The fourth proportional to 390.70, 585.43 and 253.45 is: 379.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.70 : 585.43 = 253.45 : x
  2. Step 2: Convert to fraction form
    390.70/585.43 = 253.45/x
  3. Step 3: Cross multiply
    390.70x = 585.43 × 253.45
  4. Step 4: Simplify right side
    390.70x = 148,377.23
  5. Step 5: Solve for x
    x = 148,377.23/390.70
  6. Step 6: Final answer
    x = 379.77

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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.