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Finding the Fourth Proportional to 390.40, 585.32 and 253.51

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Solution

The fourth proportional to 390.40, 585.32 and 253.51 is: 380.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.40 : 585.32 = 253.51 : x
  2. Step 2: Convert to fraction form
    390.40/585.32 = 253.51/x
  3. Step 3: Cross multiply
    390.40x = 585.32 × 253.51
  4. Step 4: Simplify right side
    390.40x = 148,384.47
  5. Step 5: Solve for x
    x = 148,384.47/390.40
  6. Step 6: Final answer
    x = 380.08

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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.