Question

Two poles 18m and. 13 m high stand upright in a playground . If their feet are 12 m apart find the distance between their top?

Answer 1

ab= 18 m
cd= 13 m
bd= 12 m
find ac
construction = draw a line ce parallel to bd
it means ebcd is rectangle 
then ec = 12 m 
angle aec= 90 
ea =ab-eb
  =18 m - 13 m
  = 5 m
ea =5 m
ea^2+ec^2=ac^2
(5m)^2+(12m)^2=ac^2
(25+144)m^2=ac^2
ac^2=169m^2
square rooting both side
ac=13m

Answer 2

Here, ED is parallel and equal to BC
To find the distance between their tops, we will have to find AD
Here as ED is parallel to BC, angle AED=90

According to the Pythagoras theorem,
AE^2 + ED^2 = AD^2
=>25+144=AD^2
=>169=AD^2
=>13=AD