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Finding the Fourth Proportional to 779.45, 1,077.08 and 639.50

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Solution

The fourth proportional to 779.45, 1,077.08 and 639.50 is: 883.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    779.45 : 1,077.08 = 639.50 : x
  2. Step 2: Convert to fraction form
    779.45/1,077.08 = 639.50/x
  3. Step 3: Cross multiply
    779.45x = 1,077.08 × 639.50
  4. Step 4: Simplify right side
    779.45x = 688,784.08
  5. Step 5: Solve for x
    x = 688,784.08/779.45
  6. Step 6: Final answer
    x = 883.69

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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.