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Finding the Fourth Proportional to 987.69, 1,363.01 and 638.38

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Solution

The fourth proportional to 987.69, 1,363.01 and 638.38 is: 880.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    987.69 : 1,363.01 = 638.38 : x
  2. Step 2: Convert to fraction form
    987.69/1,363.01 = 638.38/x
  3. Step 3: Cross multiply
    987.69x = 1,363.01 × 638.38
  4. Step 4: Simplify right side
    987.69x = 870,111.51
  5. Step 5: Solve for x
    x = 870,111.51/987.69
  6. Step 6: Final answer
    x = 880.96

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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.