Question 63893
A 18-FOOT LADDER IS LEANED AGAINST A WALL. IF THE BASE OF THE LADDER IS 7 FEET FROM THE WALL . hOW HIGH ON THE WAL WILL THE LADDER REACH?
The ladder the wall and the ground form a right traiangle with the ladder being the hypoteneuse and the wall and ground being the legs.
According to the pythagorean theorem {{{c^2=a^2+b^2}}}, where c is the length of the hypoteneuse and a and b are the lengths of the legs.
c=18 and a=7
{{{18^2=7^2+b^2}}}
{{{324=49+b^2}}}
{{{324-49=49-49+b^2}}}
{{{275=b^2}}}
{{{sqrt(275)=sqrt(b^2)}}}
{{{sqrt(25)*sqrt(11)=b}}}
{{{5*sqrt(11)=b}}}
If you need an exact answer then the wall is {{{5*sqrt(11)}}} ft tall.
If you need an approximate answer, stick it in you calculator right away:
{{{b=sqrt(275)}}} which is approximately 16.58312395 ft, round off to whatever value your teacher asks for.
Happy Calculating!!!