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Finding the Fourth Proportional to 390.68, 537.90 and 317.24

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Solution

The fourth proportional to 390.68, 537.90 and 317.24 is: 436.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.68 : 537.90 = 317.24 : x
  2. Step 2: Convert to fraction form
    390.68/537.90 = 317.24/x
  3. Step 3: Cross multiply
    390.68x = 537.90 × 317.24
  4. Step 4: Simplify right side
    390.68x = 170,643.40
  5. Step 5: Solve for x
    x = 170,643.40/390.68
  6. Step 6: Final answer
    x = 436.79

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.