waecmaths question:
In the diagram PQ is a straight line (m + n) = 110o, (n + r) =130o and (m + r ) =120o. Find the ratio of m : n : r
Option A:
2 : 3 : 4
Option B:
3 : 4 : 5
Option C:
4 : 5 : 6
Option D:
5 : 6 : 7
waecmaths solution:
$\begin{align} & m+n+r=180{}^\circ ---(i)\text{ }\!\!\{\!\!\text{ Sum of }\angle \text{s on a straight line }\!\!\}\!\!\text{ } \\ & m+n=110{}^\circ ---(ii) \\ & n+r=130{}^\circ ----(iii) \\ & m+r=120{}^\circ ----(iv) \\ & \text{Subtract }(ii)\text{ from }(i) \\ & r=70{}^\circ \\ & \text{Subtract (iii) from (i)} \\ & m=50{}^\circ \\ & \text{Subtract (iv) from (i)} \\ & n=60 \\ & m:n:r=50:60:70 \\ & m:n:r=5:6:7 \\\end{align}$
maths year:
maths topics: