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#1**+4 **

Use the cosine rule for this.

a^{2} = b^{2} + c^{2} -2bc*cos(A)

In your case 'a' is x, A is 62°, b is 2.0 and c is 2.5

.

Alan Feb 7, 2019

#2**0 **

but i cant use the cosine rule, i think i have to divide into two different 90 degree triangles

and then find the sides in the one with 62 degree inn and use sinus

sin62(1.8/2)= 0.79.....

2.5-0.79.... almost equal 1.7

then 1.7^2+1.8^2=6.148

sqrt(6.148)=2.479

but since i dont know if it was exactly 1.8 on the height then i might be at 2.4 cm

hmm

x=2.4

Guest Feb 7, 2019

edited by
Guest
Feb 7, 2019

edited by Guest Feb 7, 2019

edited by Guest Feb 7, 2019

edited by Guest Feb 7, 2019

edited by Guest Feb 7, 2019

#3**+1 **

Why can't you use the cosine rule? This question and diagram are a perfect set-up to use this rule......

ElectricPavlov
Feb 7, 2019

#4

#5**0 **

Where did you get the 1.8 from.....just a 'guestimate' ? And if you use this value for the height, then

1.8/2 would equal sin 62 .....but you MULTIPLIED the sin by sin 62......what does that do?

ElectricPavlov
Feb 7, 2019

#6**+1 **

I think your book just got a bit ahead of itself in giving you this question before discussing the cosine rule.....

cos rule give answer as 2.357 units

ElectricPavlov
Feb 7, 2019