Ask Singapore Homework?
Upload a photo of a Singapore homework and someone will email you the solution for free.
Question
secondary 4 | A Maths
One Answer Below
Anyone can contribute an answer, even non-tutors.
How to work out the steps part ii ? Tks
The shortest distance between P and R is the straight line joining them (i.e. the straight line PR).
But PR = PC + CR and then it's pretty obvious that CR = CQ. so this leads to PR = PC + CQ being the shortest.
From here, triangles PAC and RBC are similar
- angles PAC and RBC are right angles
- angles PCA and RCB are vertically opposite each other
The length ratio PA : RB is 10 : 15, which simplifies to 2 : 3.
Correspondingly, AC : BC = 2 : 3 as well due to the similarity of both triangles.
So, AC : AB = 2 : 5, and AC = 2/5 x 20 = 8 km.
See 1 Answer
You need an idea like this for part ii.
Part ii’s workings uses similar triangles.