Home / 321-688

Finding the Third Proportional to 321 and 688

Calculator

Solution

The third proportional to 321 and 688 is: 1,474.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    321 : 688 = 688 : x
  2. Step 2: Convert to fraction form
    321/688 = 688/x
  3. Step 3: Cross multiply
    321x = 688 × 688
  4. Step 4: Simplify right side
    321x = 473,344
  5. Step 5: Solve for x
    x = 473,344/321
  6. Step 6: Final answer
    x = 1,474.59

Related Problems

Find third proportional to 160.50 and 344
Half scale
Find third proportional to 642 and 1,376
Double scale
Find third proportional to 323 and 692
Similar ratio
Find third proportional to 481.50 and 1,032
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (2.14) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.