Year 12s: what will be the first way you research your future options? >>

Confusing questions

Here:

I don't know what do do first.

Reply 3

humphreyseuan19

180 degrees in a triangle
180-90=90
Two other angles add to 90
4:1 so there are five parts
90/5=18
18*4=72. Angle B
18*1 =18 Angle A

To find BC do trig

Then to find AB do Pythagoras

Original post by Steve445

I don't know what do do first.

(edited 5 years ago)

Reply 4

mqb2766

Original post by humphreyseuan19

180 degrees in a triangle
180-90=90
Two other angles add to 90
4:1 so there are five parts
90/5=18
18*4=72. Angle B
18*1 =18 Angle A

To find BC do trig

Then to find AB do Pythagoras

No need to find BC, just use trig to find AB directly (after you've worked out the angle)

Reply 5

username4426374

Okay, have I done it correct?

Reply 6

mqb2766

No, 52 is way too large, just look at the triangle.
In tan, you divide an angle by a length .which is wrong.
Just use
cos(18)

Reply 7

username4426374

Original post by mqb2766

No, 52 is way too large, just look at the triangle.
In tan, you divide an angle by a length .which is wrong.
Just use
cos(18)

So just using cos(18) will get me the answer, right?

Reply 8

Lala143

Share 90 in the ratio 1:4
90/5=18
angle x=18
Use the function Cosine because you want to find the hypotenuse and have the adjacent
Cos(18)=14/h
hypotenuse=14/Cos(18)
I don't have a calculator on me but I think that's what you do
Hope this helped

(edited 5 years ago)

Reply 9

Lala143

Just checked on my calculator: it's 14.7204 but in 3 sig. fig. it is 14.7