Home / 785.31-1,177.53-420

Finding the Fourth Proportional to 785.31, 1,177.53 and 420

Calculator

Solution

The fourth proportional to 785.31, 1,177.53 and 420 is: 629.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    785.31 : 1,177.53 = 420 : x
  2. Step 2: Convert to fraction form
    785.31/1,177.53 = 420/x
  3. Step 3: Cross multiply
    785.31x = 1,177.53 × 420
  4. Step 4: Simplify right side
    785.31x = 494,562.60
  5. Step 5: Solve for x
    x = 494,562.60/785.31
  6. Step 6: Final answer
    x = 629.77

Related Problems

Find fourth proportional to 392.66, 588.77 and 210
Half scale
Find fourth proportional to 1,570.62, 2,355.06 and 840
Double scale
Find fourth proportional to 786.31, 1,179.03 and 421
Similar ratio
Find fourth proportional to 1,177.97, 1,766.30 and 630
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.