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Finding the Fourth Proportional to 1,075.70, 1,613.55 and 643.70

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Solution

The fourth proportional to 1,075.70, 1,613.55 and 643.70 is: 965.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,075.70 : 1,613.55 = 643.70 : x
  2. Step 2: Convert to fraction form
    1,075.70/1,613.55 = 643.70/x
  3. Step 3: Cross multiply
    1,075.70x = 1,613.55 × 643.70
  4. Step 4: Simplify right side
    1,075.70x = 1,038,642.14
  5. Step 5: Solve for x
    x = 1,038,642.14/1,075.70
  6. Step 6: Final answer
    x = 965.55

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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.