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Finding the Fourth Proportional to 780.68, 1,075.16 and 648.48

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Solution

The fourth proportional to 780.68, 1,075.16 and 648.48 is: 893.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.68 : 1,075.16 = 648.48 : x
  2. Step 2: Convert to fraction form
    780.68/1,075.16 = 648.48/x
  3. Step 3: Cross multiply
    780.68x = 1,075.16 × 648.48
  4. Step 4: Simplify right side
    780.68x = 697,216.51
  5. Step 5: Solve for x
    x = 697,216.51/780.68
  6. Step 6: Final answer
    x = 893.09

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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.