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Finding the Fourth Proportional to 390.42, 539.79 and 373.20

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Solution

The fourth proportional to 390.42, 539.79 and 373.20 is: 515.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.42 : 539.79 = 373.20 : x
  2. Step 2: Convert to fraction form
    390.42/539.79 = 373.20/x
  3. Step 3: Cross multiply
    390.42x = 539.79 × 373.20
  4. Step 4: Simplify right side
    390.42x = 201,449.63
  5. Step 5: Solve for x
    x = 201,449.63/390.42
  6. Step 6: Final answer
    x = 515.98

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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.