Home / 487-688

Finding the Third Proportional to 487 and 688

Calculator

Solution

The third proportional to 487 and 688 is: 971.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    487 : 688 = 688 : x
  2. Step 2: Convert to fraction form
    487/688 = 688/x
  3. Step 3: Cross multiply
    487x = 688 × 688
  4. Step 4: Simplify right side
    487x = 473,344
  5. Step 5: Solve for x
    x = 473,344/487
  6. Step 6: Final answer
    x = 971.96

Related Problems

Find third proportional to 243.50 and 344
Half scale
Find third proportional to 974 and 1,376
Double scale
Find third proportional to 489 and 691
Similar ratio
Find third proportional to 730.50 and 1,032
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.41) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.