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Finding the Fourth Proportional to 440, 656.69 and 390.68

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Solution

The fourth proportional to 440, 656.69 and 390.68 is: 583.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    440 : 656.69 = 390.68 : x
  2. Step 2: Convert to fraction form
    440/656.69 = 390.68/x
  3. Step 3: Cross multiply
    440x = 656.69 × 390.68
  4. Step 4: Simplify right side
    440x = 256,555.65
  5. Step 5: Solve for x
    x = 256,555.65/440
  6. Step 6: Final answer
    x = 583.08

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.