28.The figure below shows△M N Qcrossed byRP. PointsPandRbisect their respective sides of the
triangle.
N M
Q
15 d
P 9 d R
a)The anglesQ^= 15dandRP Q^ = 9dare given in the large triangle; determine the value ofM^ in
terms ofd.
b)You are now told thatRP Q^ has a measure of 60 ◦. Solve for the value ofd. Give your answer as an
exact fractional value.
29.Calculateaandb:
T
R
P
S
Q
a
15
b
4
9
b
30.△P QRand△P SRare equilateral triangles. Prove thatP QRSis a rhombus.
12
匀^12
倀
刀
儀
31.LM N Ois a quadrilateral withLM=LOand diagonals that intersect atSsuch thatM S=SO. Prove
that:
L
N
M S O
a)MLS^ =SLO^
b)△LON△LM N
c)M O?LN
280 7.5. Chapter summary