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Finding the Fourth Proportional to 720.24, 993.76 and 421.40

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Solution

The fourth proportional to 720.24, 993.76 and 421.40 is: 581.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.24 : 993.76 = 421.40 : x
  2. Step 2: Convert to fraction form
    720.24/993.76 = 421.40/x
  3. Step 3: Cross multiply
    720.24x = 993.76 × 421.40
  4. Step 4: Simplify right side
    720.24x = 418,770.46
  5. Step 5: Solve for x
    x = 418,770.46/720.24
  6. Step 6: Final answer
    x = 581.43

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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.