Home / 780.94-1,077.55-486

Finding the Fourth Proportional to 780.94, 1,077.55 and 486

Calculator

Solution

The fourth proportional to 780.94, 1,077.55 and 486 is: 670.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.94 : 1,077.55 = 486 : x
  2. Step 2: Convert to fraction form
    780.94/1,077.55 = 486/x
  3. Step 3: Cross multiply
    780.94x = 1,077.55 × 486
  4. Step 4: Simplify right side
    780.94x = 523,690.82
  5. Step 5: Solve for x
    x = 523,690.82/780.94
  6. Step 6: Final answer
    x = 670.59

Related Problems

Find fourth proportional to 390.47, 538.78 and 243
Half scale
Find fourth proportional to 1,561.88, 2,155.11 and 972
Double scale
Find fourth proportional to 781.94, 1,078.93 and 487
Similar ratio
Find fourth proportional to 1,171.41, 1,616.33 and 729
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.