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Finding the Fourth Proportional to 390.88, 585.64 and 253.77

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Solution

The fourth proportional to 390.88, 585.64 and 253.77 is: 380.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.88 : 585.64 = 253.77 : x
  2. Step 2: Convert to fraction form
    390.88/585.64 = 253.77/x
  3. Step 3: Cross multiply
    390.88x = 585.64 × 253.77
  4. Step 4: Simplify right side
    390.88x = 148,617.86
  5. Step 5: Solve for x
    x = 148,617.86/390.88
  6. Step 6: Final answer
    x = 380.21

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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.