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Finding the Fourth Proportional to 390.65, 585.63 and 253.60

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Solution

The fourth proportional to 390.65, 585.63 and 253.60 is: 380.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.65 : 585.63 = 253.60 : x
  2. Step 2: Convert to fraction form
    390.65/585.63 = 253.60/x
  3. Step 3: Cross multiply
    390.65x = 585.63 × 253.60
  4. Step 4: Simplify right side
    390.65x = 148,514.30
  5. Step 5: Solve for x
    x = 148,514.30/390.65
  6. Step 6: Final answer
    x = 380.18

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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.