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Finding the Fourth Proportional to 720.20, 993.74 and 421.40

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Solution

The fourth proportional to 720.20, 993.74 and 421.40 is: 581.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.20 : 993.74 = 421.40 : x
  2. Step 2: Convert to fraction form
    720.20/993.74 = 421.40/x
  3. Step 3: Cross multiply
    720.20x = 993.74 × 421.40
  4. Step 4: Simplify right side
    720.20x = 418,754.96
  5. Step 5: Solve for x
    x = 418,754.96/720.20
  6. Step 6: Final answer
    x = 581.45

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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.