Answer with explanation:
Length of ladder= 11 meter
Distance from foot of ladder to base of wall = 4 meter
Let height of Wall upto which Ladder reach = h meter
By using Pythagorean theorem
⇒(Length of ladder)²=(Height of Wall upto which Ladder reach)² + ( Distance from foot of ladder to base of wall)²
⇒(11)²=(Height of Wall upto which Ladder reach)²+4²
Subtracting 16 from both sides
⇒121 -16 = (Height of Wall upto which Ladder reach)²
⇒105 = (Height of Wall upto which Ladder reach)²
⇒ Height of Wall upto which Ladder reach