Question

shown that the points A(-1,2),B(5,2) and C(2,5) are the vertices of an isosceles triangle find the area of ABC

Answer 1

I found the answer to AB,BC,and AC now can anyone tell me how to find the area

Answer 2

area = 1/2 * base*height

Answer 3

The answer to AB=6,BC=\/18,AC=\/18

Answer 4

It doesn't really matter what way you find the base or height

Answer 5

I know the formula to find the area how am i suppose to find the hieght?

Answer 6

find the midpoint of AB, call that D, then find the length of CD
Area = CD x AB x 1/2

Answer 7

the midpoint is (2,2)

Answer 8

ok so I get the height 3

Answer 9

What the hell just happened?? I Answered my own question I found the answer..I'm a genius..lol Thanx for ya'll help

Answer 10

wait a sec

Answer 11

You found the 3 distances right?

Answer 12

yes

Answer 13

it says find the length perpendicular form a to bc

Answer 14

from*

Answer 15

No you don't need that much trouble for the area. Ever heard of Heron's Formula?

Answer 16

no...If its easier that way can you please explain it to me?

Answer 17

Ohkay, so if the lengths of the 3 sides of a triangle are a,b and c, then,

semi-perimeter (half perimeter) = \(\large s = \frac{a+b+c}{2}\)

Then, area 'A' of the triangle is:

\[A = \sqrt{s(s-a)(s-b)(s-c)}\]


(believe it's easier than it looks)

Answer 18

*believe me

Answer 19

and one more thing sometimes they ask you to find the length perpendicular ..like from A to BC

Answer 20

let me look at the formula for a moment

Answer 21

Ohkay if they have asked you to find the length of the perpendicular, then in this particular case, the perpendicular meets the opposite side at its mid-point (since this is an isosceles triangle)

Answer 22

what does "large s" and "frac" I know but just making sure

Answer 23

stand for*

Answer 24

Oh seems like the codes haven't processed, just refresh your tab once, that would make it alright.

Answer 25

ok

Answer 26

ok now their good I'm gonna look at em for a moment

Answer 27

I've pretty much got it but what does the "s" stand for?

Answer 28

s = (a+b+c)/2

simply this^. (called the semi-perimeter)

Answer 29

wow that pretty much solves the whole thing in a bit thanx again your incredible

Answer 30

ok so lets look at the perpendicular question what will i have to do if its not an isosceles triangle ?

Answer 31

Thanx for your Help I'm gonna go ahead and give my test bye

Answer 32

Hmm, that's difficult, let me think about ti and reply.

All the best for your test man! :]

Answer 33

Thank you