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Finding the Fourth Proportional to 521.55, 719.79 and 390.33

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Solution

The fourth proportional to 521.55, 719.79 and 390.33 is: 538.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    521.55 : 719.79 = 390.33 : x
  2. Step 2: Convert to fraction form
    521.55/719.79 = 390.33/x
  3. Step 3: Cross multiply
    521.55x = 719.79 × 390.33
  4. Step 4: Simplify right side
    521.55x = 280,955.63
  5. Step 5: Solve for x
    x = 280,955.63/521.55
  6. Step 6: Final answer
    x = 538.69

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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.