Home / 423-780

Finding the Third Proportional to 423 and 780

Calculator

Solution

The third proportional to 423 and 780 is: 1,438.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    423 : 780 = 780 : x
  2. Step 2: Convert to fraction form
    423/780 = 780/x
  3. Step 3: Cross multiply
    423x = 780 × 780
  4. Step 4: Simplify right side
    423x = 608,400
  5. Step 5: Solve for x
    x = 608,400/423
  6. Step 6: Final answer
    x = 1,438.30

Related Problems

Find third proportional to 211.50 and 390
Half scale
Find third proportional to 846 and 1,560
Double scale
Find third proportional to 425 and 784
Similar ratio
Find third proportional to 634.50 and 1,170
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.84) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.