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Finding the Fourth Proportional to 500.85, 690.93 and 390.69

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Solution

The fourth proportional to 500.85, 690.93 and 390.69 is: 538.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    500.85 : 690.93 = 390.69 : x
  2. Step 2: Convert to fraction form
    500.85/690.93 = 390.69/x
  3. Step 3: Cross multiply
    500.85x = 690.93 × 390.69
  4. Step 4: Simplify right side
    500.85x = 269,939.44
  5. Step 5: Solve for x
    x = 269,939.44/500.85
  6. Step 6: Final answer
    x = 538.96

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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.