Home / 669.88-923.69-420.90

Finding the Fourth Proportional to 669.88, 923.69 and 420.90

Calculator

Solution

The fourth proportional to 669.88, 923.69 and 420.90 is: 580.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    669.88 : 923.69 = 420.90 : x
  2. Step 2: Convert to fraction form
    669.88/923.69 = 420.90/x
  3. Step 3: Cross multiply
    669.88x = 923.69 × 420.90
  4. Step 4: Simplify right side
    669.88x = 388,781.12
  5. Step 5: Solve for x
    x = 388,781.12/669.88
  6. Step 6: Final answer
    x = 580.37

Related Problems

Find fourth proportional to 334.94, 461.85 and 210.45
Half scale
Find fourth proportional to 1,339.76, 1,847.38 and 841.80
Double scale
Find fourth proportional to 670.88, 925.07 and 421.90
Similar ratio
Find fourth proportional to 1,004.82, 1,385.54 and 631.35
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.