Home » ∠ E = 900 » EF = 3 cm » If DE = 4 cm » In ∆ DEF » What is the length of side DF? » In ∆ DEF, ∠ E = 900 , If DE = 4 cm, EF = 3 cm, What is the length of side DF?

In ∆ DEF, ∠ E = 900 , If DE = 4 cm, EF = 3 cm, What is the length of side DF?

Solution:

In ∆ DEF, ∠ E = 90⁰ [Given]

∴ DF² = DE² + EF² [By Pythagoras theorem]

∴ DF² = 4² + 3²

∴ DF² = 16 + 9

∴ DF² = 25

∴ DF = √25

∴ DF = 5 cm

Ans. The length of DF is 5 cm.