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Finding the Fourth Proportional to 977.81, 1,349.40 and 645.99

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Solution

The fourth proportional to 977.81, 1,349.40 and 645.99 is: 891.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    977.81 : 1,349.40 = 645.99 : x
  2. Step 2: Convert to fraction form
    977.81/1,349.40 = 645.99/x
  3. Step 3: Cross multiply
    977.81x = 1,349.40 × 645.99
  4. Step 4: Simplify right side
    977.81x = 871,698.91
  5. Step 5: Solve for x
    x = 871,698.91/977.81
  6. Step 6: Final answer
    x = 891.49

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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.