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Finding the Fourth Proportional to 740.78, 1,111.35 and 647.36

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Solution

The fourth proportional to 740.78, 1,111.35 and 647.36 is: 971.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    740.78 : 1,111.35 = 647.36 : x
  2. Step 2: Convert to fraction form
    740.78/1,111.35 = 647.36/x
  3. Step 3: Cross multiply
    740.78x = 1,111.35 × 647.36
  4. Step 4: Simplify right side
    740.78x = 719,444.09
  5. Step 5: Solve for x
    x = 719,444.09/740.78
  6. Step 6: Final answer
    x = 971.20

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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.