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Finding the Fourth Proportional to 428.40, 590.40 and 403.20

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Solution

The fourth proportional to 428.40, 590.40 and 403.20 is: 555.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.40 : 590.40 = 403.20 : x
  2. Step 2: Convert to fraction form
    428.40/590.40 = 403.20/x
  3. Step 3: Cross multiply
    428.40x = 590.40 × 403.20
  4. Step 4: Simplify right side
    428.40x = 238,049.28
  5. Step 5: Solve for x
    x = 238,049.28/428.40
  6. Step 6: Final answer
    x = 555.67

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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.