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Finding the Fourth Proportional to 1,988.20, 2,980.42 and 947.65

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Solution

The fourth proportional to 1,988.20, 2,980.42 and 947.65 is: 1,420.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,988.20 : 2,980.42 = 947.65 : x
  2. Step 2: Convert to fraction form
    1,988.20/2,980.42 = 947.65/x
  3. Step 3: Cross multiply
    1,988.20x = 2,980.42 × 947.65
  4. Step 4: Simplify right side
    1,988.20x = 2,824,385.19
  5. Step 5: Solve for x
    x = 2,824,385.19/1,988.20
  6. Step 6: Final answer
    x = 1,420.58

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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.