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Finding the Fourth Proportional to 1,390.86, 2,085.93 and 649.98

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Solution

The fourth proportional to 1,390.86, 2,085.93 and 649.98 is: 974.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,390.86 : 2,085.93 = 649.98 : x
  2. Step 2: Convert to fraction form
    1,390.86/2,085.93 = 649.98/x
  3. Step 3: Cross multiply
    1,390.86x = 2,085.93 × 649.98
  4. Step 4: Simplify right side
    1,390.86x = 1,355,812.78
  5. Step 5: Solve for x
    x = 1,355,812.78/1,390.86
  6. Step 6: Final answer
    x = 974.80

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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.