Thread: apply complex mathematical concepts to building and constructions principle

1. apply complex mathematical concepts to building and constructions principle

Hi, i urgently need help with this subject, i need to complete it for a course i am wanting to enrol in, but maths wasn't for me, now i am stuck. i need help with this question,

Find the area of the triangle with the lengths 2.87 m, 3.69 m and 4.58 m
565 mm, 823 mm and 1.08 m

i have no idea how to do this,

2. Originally Posted by seran
Hi, i urgently need help with this subject, i need to complete it for a course i am wanting to enrol in, but maths wasn't for me, now i am stuck. i need help with this question,

Find the area of the triangle with the lengths 2.87 m, 3.69 m and 4.58 m
565 mm, 823 mm and 1.08 m

i have no idea how to do this,

Use Heron's Formula.

If $\displaystyle a, b, c$ are the sides of the triangle, let $\displaystyle s$ be the semi-perimeter. I.e. $\displaystyle s = \frac{a + b + c}{2}$.

Then the Area is

$\displaystyle A = \sqrt{s(s - a)(s - b)(s - c)}$.

3. sorry ur going to think im pretty stupid, i did say im hopless in mtahs, but where did u get the 2 and s from???

you've lost me sorry

4. Follow the instructions I gave you.

Call the three sides of your triangle $\displaystyle a, b, c$.

Then work out the semiperimeter:

$\displaystyle s = \frac{a + b + c}{2}$.

Then work out the Area

$\displaystyle A = \sqrt{s(s - a)(s - b)(s - c)}$.

5. Hello, seran!

If you can't handle Heron's Formula,
. . then you must know some Trigonometry.

Find the area of the triangle with the lengths 2.87 m, 3.69 m and 4.58 m

565 mm, 823 mm and 1.08 m .
What are these?
We have a triangle:
Code:
            C
o
*  *
b  *     *  a
*        *
*           *
*              *
A *  *  *  *  *  *  * B
c
We are given: .$\displaystyle \begin{array}{ccc}a &=& 2.87 \\ b &=& 3.69 \\ c &=& 4.58 \end{array}$

We can find angle $\displaystyle A$ with: .$\displaystyle \cos A \:=\:\frac{b^2+c^2 - a^2}{2bc}$

Then the area is: .$\displaystyle \tfrac{1}{2}bc\sin A$

If all this is meaningless to you,
and you're really "hopless in math",
. . . . just skip the problem.

6. Hi seran,

If you need this subject for a course you want to enroll in,
why is this topic important for the course ?

Will you have difficulty on the course without it ?
Try the question, you might be surprised how easy it can get.

As Soroban showed,

If you have the 3 sides of a triangle,
you can find any angle using the Law of Cosines, or Cosine Rule

Then,
you can find the area of a triangle if you have all 3 dimensions at any of the 3 corners,
using the triangle area formula, for a triangle for which you are not given the perpendicular height and base.

7. I want to study architecture and one of the pre-req is that i have to have completed maths in year 12, which i never did, so the course i will be doing am assuming won't involve algebra etc, just measure etc. i haven't done maths since 1993, thats 17 years. so really nothing is sinking in and is getting really depresed cause i feel so stupid. thanks all for your helps.

8. Hi, thank you all, ooo i feel stupid, no i don't know trig, like i mentioned i did maths about 17 years ago, and really never paid attention to the teacher because maths was never my best friend. so i didnt take it up in year 12 either. Now i want to study from home architecture and one of the pre-req is that i have to have completed maths in year 12. Or to do this subject, i think i need a private tutor.

9. Originally Posted by seran
I want to study architecture and one of the pre-req is that i have to have completed maths in year 12, which i never did, so the course i will be doing am assuming won't involve algebra etc, just measure etc. i haven't done maths since 1993, thats 17 years. so really nothing is sinking in and is getting really depresed cause i feel so stupid. thanks all for your helps.
You're in for a suprise! You're gonna need a lot of math there, buddy!

Check it out.

Architecture Degree Program Requirements

10. ooo, know i feel even worse, gota get a tutor, thnax for that,