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Finding the Fourth Proportional to 685.51, 946.06 and 390.87

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Solution

The fourth proportional to 685.51, 946.06 and 390.87 is: 539.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.51 : 946.06 = 390.87 : x
  2. Step 2: Convert to fraction form
    685.51/946.06 = 390.87/x
  3. Step 3: Cross multiply
    685.51x = 946.06 × 390.87
  4. Step 4: Simplify right side
    685.51x = 369,786.47
  5. Step 5: Solve for x
    x = 369,786.47/685.51
  6. Step 6: Final answer
    x = 539.44

Related Problems

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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.