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Finding the Fourth Proportional to 1,390.59, 2,086.58 and 649.89

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Solution

The fourth proportional to 1,390.59, 2,086.58 and 649.89 is: 975.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,390.59 : 2,086.58 = 649.89 : x
  2. Step 2: Convert to fraction form
    1,390.59/2,086.58 = 649.89/x
  3. Step 3: Cross multiply
    1,390.59x = 2,086.58 × 649.89
  4. Step 4: Simplify right side
    1,390.59x = 1,356,047.48
  5. Step 5: Solve for x
    x = 1,356,047.48/1,390.59
  6. Step 6: Final answer
    x = 975.16

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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.