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Finding the Fourth Proportional to 521.80, 720.13 and 390.58

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Solution

The fourth proportional to 521.80, 720.13 and 390.58 is: 539.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    521.80 : 720.13 = 390.58 : x
  2. Step 2: Convert to fraction form
    521.80/720.13 = 390.58/x
  3. Step 3: Cross multiply
    521.80x = 720.13 × 390.58
  4. Step 4: Simplify right side
    521.80x = 281,268.38
  5. Step 5: Solve for x
    x = 281,268.38/521.80
  6. Step 6: Final answer
    x = 539.03

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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.