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Finding the Fourth Proportional to 1,389.96, 1,917.51 and 917.19

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Solution

The fourth proportional to 1,389.96, 1,917.51 and 917.19 is: 1,265.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,389.96 : 1,917.51 = 917.19 : x
  2. Step 2: Convert to fraction form
    1,389.96/1,917.51 = 917.19/x
  3. Step 3: Cross multiply
    1,389.96x = 1,917.51 × 917.19
  4. Step 4: Simplify right side
    1,389.96x = 1,758,721.00
  5. Step 5: Solve for x
    x = 1,758,721.00/1,389.96
  6. Step 6: Final answer
    x = 1,265.30

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Half scale
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Double scale
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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.