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Finding the Fourth Proportional to 784.16, 1,081.90 and 485.36

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Solution

The fourth proportional to 784.16, 1,081.90 and 485.36 is: 669.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    784.16 : 1,081.90 = 485.36 : x
  2. Step 2: Convert to fraction form
    784.16/1,081.90 = 485.36/x
  3. Step 3: Cross multiply
    784.16x = 1,081.90 × 485.36
  4. Step 4: Simplify right side
    784.16x = 525,110.98
  5. Step 5: Solve for x
    x = 525,110.98/784.16
  6. Step 6: Final answer
    x = 669.65

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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.