Ask Singapore Homework?

Upload a photo of a Singapore homework and someone will email you the solution for free.



Question

secondary 3 | A Maths
One Answer Below

This question need another answer.

Answer This Question
trisha
Trisha

secondary 3 chevron_right A Maths chevron_right Singapore

help

Date Posted: 1 month ago
Views: 33
J
J
1 month ago
Use cosine rule to find ∠A and do the same to find ∠B.

Cosine rule :
① c² = a² + b² - 2ab cos ∠C
Or
② cos ∠C = (a² + b² - c²) / 2ab

Then 180° - ∠A - ∠B = ∠C (Angle sum of triangle)

You can just take a to be 2 units, b to be 3 units and c to be 4 units.



Alternatively,


Use variant ② of cosine rule :

② cos ∠C = (a² + b² - c²) / 2ab

then ∠C = cos-¹ [(a² + b² - c²) / 2ab]


sin ∠C = sin (cos-¹ [(a² + b² - c²) / 2ab])

See 1 Answer

done {{ upvoteCount }} Upvotes
clear {{ downvoteCount * -1 }} Downvotes
Danny Low
Danny Low's answer
233 answers (Tutor Details)
Hope this helps
trisha
Trisha
1 month ago
Thats not cosine rule
J
J
1 month ago
The format is correct.

He just wrote 'sin' by accident instead of 'cos'