Home / 355-643

Finding the Third Proportional to 355 and 643

Calculator

Solution

The third proportional to 355 and 643 is: 1,164.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    355 : 643 = 643 : x
  2. Step 2: Convert to fraction form
    355/643 = 643/x
  3. Step 3: Cross multiply
    355x = 643 × 643
  4. Step 4: Simplify right side
    355x = 413,449
  5. Step 5: Solve for x
    x = 413,449/355
  6. Step 6: Final answer
    x = 1,164.65

Related Problems

Find third proportional to 177.50 and 321.50
Half scale
Find third proportional to 710 and 1,286
Double scale
Find third proportional to 357 and 647
Similar ratio
Find third proportional to 532.50 and 964.50
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.81) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.