Cycling UK Forum

can anyone please explain how to work out the angles r,s,q and t in question F? ive tried in vain,i`m sure theres not enough info provided.

Hi Johnonthetyne

All angles in a triangle = 180*

for "T" add 65 and 45 then subtract that from 180 = 70*

R = 45* opposite angles in a parralellogram

S= 45* as angles "R" and "S" = "T" 45*

Q 65* opposite angles etc

do I get a gold star

any one else to check the above

edit, just to clarify "S" the line between angles "R" and "S" is the same as the line between "T" and 45*

thanks for that fw, will look at book again.

I think (as no great trigonometer should that be trigonometrist?) that ferrit worrier is correct if you assume that the relevant lines are parallel, altough there is no indication that that is so. Without that, Idon't think there is enough info. Looking at the other questions, none is very difficult so this problem must be pretty straightforward.

thirdcrank wrote:I think (as no great trigonometer should that be trigonometrist?) that ferrit worrier is correct if you assume that the relevant lines are parallel, altough there is no indication that that is so. Without that, Idon't think there is enough info. Looking at the other questions, none is very difficult so this problem must be pretty straightforward.

I agree but wondered if the shaded angles are supposed to show that all are equal (rather than just opposite pairs); which would mean the lines are parallel.

Not enough info!

Q and T are easy enough because angles add up easily, but the other diagonal line describing R and S could be anything as they don't say what relationship that line has with the other.

Q equals 65deg
T equals 180-(65+45)=70deg

You can say, however, that R and S are equal, but nowt else.

If it's parallel, as I suspect it is, R=S=45deg


PS,
Thinking about it, are the two horizontal lines parallel? Dunno! They don't say!

When I studied maths, parallel lines were denoted with two dashes on each line.

ferrit worrier's calculations are right. I think the fact that some of the other angles are shaded indicates that they are all equal, which I think ensures that the appropriate pairs of lines are parallel.

thanx everyone, makes sense now, knew id be able to sort it on here.

Its even easier than that:
Shaded angles must be identical because they have identical markings even if of an unfamiliar (to me) style

t= 180-(45+65)...........Angle sum of a triangle
t = 70

Shaded angles =t=70....Opposite angles

q=65......................Alternate angles

r= 180-(70+q)..........Angle sum of a triangle
r=180-(70+65)
r=45

s=r=45...................Alternate angles

If you go on to calculate the unseen third angle of that triangle you will prove that there are three sets of parallel lines.

I have an unfair advantage here - my lad took his GCSE this year