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Finding the Fourth Proportional to 830.40, 1,245.64 and 419.05

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Solution

The fourth proportional to 830.40, 1,245.64 and 419.05 is: 628.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    830.40 : 1,245.64 = 419.05 : x
  2. Step 2: Convert to fraction form
    830.40/1,245.64 = 419.05/x
  3. Step 3: Cross multiply
    830.40x = 1,245.64 × 419.05
  4. Step 4: Simplify right side
    830.40x = 521,984.39
  5. Step 5: Solve for x
    x = 521,984.39/830.40
  6. Step 6: Final answer
    x = 628.60

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.