Home / 805.78-1,207.86-394.30

Finding the Fourth Proportional to 805.78, 1,207.86 and 394.30

Calculator

Solution

The fourth proportional to 805.78, 1,207.86 and 394.30 is: 591.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    805.78 : 1,207.86 = 394.30 : x
  2. Step 2: Convert to fraction form
    805.78/1,207.86 = 394.30/x
  3. Step 3: Cross multiply
    805.78x = 1,207.86 × 394.30
  4. Step 4: Simplify right side
    805.78x = 476,259.20
  5. Step 5: Solve for x
    x = 476,259.20/805.78
  6. Step 6: Final answer
    x = 591.05

Related Problems

Find fourth proportional to 402.89, 603.93 and 197.15
Half scale
Find fourth proportional to 1,611.56, 2,415.72 and 788.60
Double scale
Find fourth proportional to 806.78, 1,209.36 and 395.30
Similar ratio
Find fourth proportional to 1,208.67, 1,811.79 and 591.45
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.