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Finding the Fourth Proportional to 838.72, 1,256.40 and 655.20

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Solution

The fourth proportional to 838.72, 1,256.40 and 655.20 is: 981.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    838.72 : 1,256.40 = 655.20 : x
  2. Step 2: Convert to fraction form
    838.72/1,256.40 = 655.20/x
  3. Step 3: Cross multiply
    838.72x = 1,256.40 × 655.20
  4. Step 4: Simplify right side
    838.72x = 823,193.28
  5. Step 5: Solve for x
    x = 823,193.28/838.72
  6. Step 6: Final answer
    x = 981.49

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Double scale
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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.