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Finding the Fourth Proportional to 1,378.80, 2,069.15 and 648.45

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Solution

The fourth proportional to 1,378.80, 2,069.15 and 648.45 is: 973.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,378.80 : 2,069.15 = 648.45 : x
  2. Step 2: Convert to fraction form
    1,378.80/2,069.15 = 648.45/x
  3. Step 3: Cross multiply
    1,378.80x = 2,069.15 × 648.45
  4. Step 4: Simplify right side
    1,378.80x = 1,341,737.08
  5. Step 5: Solve for x
    x = 1,341,737.08/1,378.80
  6. Step 6: Final answer
    x = 973.12

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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.