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Finding the Fourth Proportional to 520.40, 717.72 and 389.72

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Solution

The fourth proportional to 520.40, 717.72 and 389.72 is: 537.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    520.40 : 717.72 = 389.72 : x
  2. Step 2: Convert to fraction form
    520.40/717.72 = 389.72/x
  3. Step 3: Cross multiply
    520.40x = 717.72 × 389.72
  4. Step 4: Simplify right side
    520.40x = 279,709.84
  5. Step 5: Solve for x
    x = 279,709.84/520.40
  6. Step 6: Final answer
    x = 537.49

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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.