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Finding the Fourth Proportional to 784.80, 1,175.72 and 419.76

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Solution

The fourth proportional to 784.80, 1,175.72 and 419.76 is: 628.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    784.80 : 1,175.72 = 419.76 : x
  2. Step 2: Convert to fraction form
    784.80/1,175.72 = 419.76/x
  3. Step 3: Cross multiply
    784.80x = 1,175.72 × 419.76
  4. Step 4: Simplify right side
    784.80x = 493,518.13
  5. Step 5: Solve for x
    x = 493,518.13/784.80
  6. Step 6: Final answer
    x = 628.85

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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.