Get an answer in 5 minutes

We'll notify as soon as your question has been answered.

Plus iconAsk a question to our educators
MATHS
Asked by Josh

How do I find the area of a triangle when I only know the three side lengths?

There are two methods to find the area: Method 1: use cosine rule to find out one angle: cosA=(b^2+c^2-a^2)/2bc, and then use area formula 1/2bcSinA to work out the area. Method 2: use Heron's formula which is Area=(s(s-a)(s-b)(s-c))^1/2, where s=(a+b+c)/2, but neither A-level nor GCSE will use Heron's formula to solve area for triangle, and I believe Heron's formula is not in mark scheme, so you don't need to learn the second method. The first method is more common. I hope you find this answer helpful.

Zhen's profile picture
Verified
Zhen Hua
·

8.2k students helped

By Herons formula , you can find the area of the triangle

Hi, the most straightforward answer to this inquiry would be by using Heron's formula which is: Area = sqrt( p ( p - a ) ( p - b ) ( p -c ) ) where a, b, and c are the lengths of the sides of the triangle, and p is 1/2 of the perimeter (i.e. (a + b + c) / 2). This formula works for any type of triangle, as long as a, b, and c are actually valid lengths to form a triangle. Another way involving trigonometry is to use the cosine law, but that will involve having to calculate the angles for the triangle.

Nigel's profile picture
Nigel Rimando
·

118 students helped

use the cosine rule b^2 + C^2 -A^2/ 2bc to find the cosA angle. then do cos-1 to find the angle. then use sine rule= 1/2AB sinC to find the area Hope it works

Fowzi's profile picture
Verified
Fowzi Begum
·

5.3k students helped

You need to know at least one angle otherwise it is impossible

Similar Maths questions

Maths

Asked by Aliehs

Terms

What is Q&A on Scoodle?

At Scoodle we understand that everyone learns in a different way. Some people learn through practice, using essays and notes; others prefer video lessons to watch and learn, some just need help with a specifically hard question, while some learn best 1-on-1 tutoring sessions. At Scoodle we cater for all types of learning styles and needs. From GCSE Maths video lessons to A-level English essays and specialist educators in every subject - we’ve got you covered.

Faces of students on ScoodleFaces of students on ScoodleFaces of students on Scoodle
Scoodle has helped over 131,000 students so far

5 Maths tutors available now

Abdur's profile picture
Verified
Verified

Abdur Khan

Online lessons

Second year dental student, happy to help :)

Hi, my name is Abdur and I’m currently studying Dentistry at the University of Bristol. I’d describe myself as a kind and friendly person who loves to teach using evidence-based techniques. As a dental student, a lot of my time is spent learning but also teaching others as it reinforces the knowledge I’ve gained from lectures, seminars and clinical sessions. I’d describing my style of teaching as interactive and personal as everyone has their own way of grasping topics. What sets my teaching apart from others is that it integrates core topics and links the common themes which cements the information to a deeper level of understanding. This is something I’ve used in my own studies which has helped me to ranked in the top 10 for the end of Year 1 exams and over achieve over 70% in end of Year 2 exams. I have been tutoring and mentoring students since 2016. What I’ve learnt from this experience is that building confidence in students is one of the key components to boosting grades. I highlight strengths and weaknesses so we can reinforce the areas which require more attention. This is through evidence-based teaching called active recall. The purpose of this method is to stimulate the mind through questioning rather than passive learning. Passive learning is something many students are guilty of which often leads to average grades. Through active learning it highlights areas that requires more attention. Spaced repetition will help to prevent forgetting important information and enables long term storage of knowledge which is crucial for exams!

£20Per hour
331Students helped

Need help with Maths?

Getting expert help from a tutor is a great way to improve your Maths grades.

Badge showing the text 'New'Discover learning resources by tutors

Learn Maths with Video Lessons
GCSE Maths - Numbers
1hr 28m · 8 videos
Paja's profile picture
Paja Kruzikova
·

696 students helped

GCSE Maths - Numbers
Quadratic Inequalities
28m · 3 videos
Iqbal's profile picture
Iqbal Lokman
·

1.5k students helped

Quadratic Inequalities
GCSE Maths - Ratios
1hr 32m · 9 videos
Paja's profile picture
Paja Kruzikova
·

696 students helped

GCSE Maths - Ratios
GCSE Maths - Algebra A
56m · 6 videos
Paja's profile picture
Paja Kruzikova
·

696 students helped

GCSE Maths - Algebra A
GCSE Maths - Algebra B
1hr 14m · 7 videos
Paja's profile picture
Paja Kruzikova
·

696 students helped

GCSE Maths - Algebra B
GCSE Maths - Algebra C
1hr 27m · 9 videos
Paja's profile picture
Paja Kruzikova
·

696 students helped

GCSE Maths - Algebra C