A triangle has sides a,b,c and angles A,B,C with a opposite A etc. If a=4,b=3,A=40, what is the area of the triangle?

First use the sine rule (that a/sin(A)=b/sin(B)=c/sin(C)) to find the value of B. a/sin(A)=b/sin(B) so B=arcsin(bsin(A)/a) which is approximately equal to 28.82. Since the angles of a triangle have 180 degrees we then know that C is roughly equal to 111.18. Now we can use S=ab*sin(C)/2 where S is the area of the triangle so the area is roughly 5.59.

Answered by Maths tutor

2365 Views

See similar Maths A Level tutors

Related Maths A Level answers

All answers ▸

A spherical balloon of radius r cm has volume Vcm^3 , where V =4/3 * pi * r^3. The balloon is inflated at a constant rate of 10 cm^3 s^-1 . Find the rate of increase of r when r = 8.


What is 7 to the power of 8? (


Prove that the derivative of tan(x) is sec^2(x).


Find the coordinates of the sationary points on the curve x^2 -xy+y^2=12


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences