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Finding the Fourth Proportional to 890.05, 1,228.21 and 491.71

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Solution

The fourth proportional to 890.05, 1,228.21 and 491.71 is: 678.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    890.05 : 1,228.21 = 491.71 : x
  2. Step 2: Convert to fraction form
    890.05/1,228.21 = 491.71/x
  3. Step 3: Cross multiply
    890.05x = 1,228.21 × 491.71
  4. Step 4: Simplify right side
    890.05x = 603,918.84
  5. Step 5: Solve for x
    x = 603,918.84/890.05
  6. Step 6: Final answer
    x = 678.52

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1.5x scale

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.