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Finding the Fourth Proportional to 780.12, 1,075.74 and 485.33

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Solution

The fourth proportional to 780.12, 1,075.74 and 485.33 is: 669.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.12 : 1,075.74 = 485.33 : x
  2. Step 2: Convert to fraction form
    780.12/1,075.74 = 485.33/x
  3. Step 3: Cross multiply
    780.12x = 1,075.74 × 485.33
  4. Step 4: Simplify right side
    780.12x = 522,088.89
  5. Step 5: Solve for x
    x = 522,088.89/780.12
  6. Step 6: Final answer
    x = 669.24

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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.