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Finding the Fourth Proportional to 611.10, 843.11 and 390.18

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Solution

The fourth proportional to 611.10, 843.11 and 390.18 is: 538.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    611.10 : 843.11 = 390.18 : x
  2. Step 2: Convert to fraction form
    611.10/843.11 = 390.18/x
  3. Step 3: Cross multiply
    611.10x = 843.11 × 390.18
  4. Step 4: Simplify right side
    611.10x = 328,964.79
  5. Step 5: Solve for x
    x = 328,964.79/611.10
  6. Step 6: Final answer
    x = 538.32

Related Problems

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Double scale
Find fourth proportional to 612.10, 844.49 and 391.18
Similar ratio
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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.