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Finding the Fourth Proportional to 521.17, 719.66 and 390.85

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Solution

The fourth proportional to 521.17, 719.66 and 390.85 is: 539.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    521.17 : 719.66 = 390.85 : x
  2. Step 2: Convert to fraction form
    521.17/719.66 = 390.85/x
  3. Step 3: Cross multiply
    521.17x = 719.66 × 390.85
  4. Step 4: Simplify right side
    521.17x = 281,278.29
  5. Step 5: Solve for x
    x = 281,278.29/521.17
  6. Step 6: Final answer
    x = 539.71

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1.5x scale

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.