Home / 405.50-643

Finding the Third Proportional to 405.50 and 643

Calculator

Solution

The third proportional to 405.50 and 643 is: 1,019.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    405.50 : 643 = 643 : x
  2. Step 2: Convert to fraction form
    405.50/643 = 643/x
  3. Step 3: Cross multiply
    405.50x = 643 × 643
  4. Step 4: Simplify right side
    405.50x = 413,449
  5. Step 5: Solve for x
    x = 413,449/405.50
  6. Step 6: Final answer
    x = 1,019.60

Related Problems

Find third proportional to 202.75 and 321.50
Half scale
Find third proportional to 811 and 1,286
Double scale
Find third proportional to 408 and 646
Similar ratio
Find third proportional to 608.25 and 964.50
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.59) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.