help plz (1 Viewer)

[atakach99]

ok this one is seems easy but everytime i try it i get a different answer from the back of the book

Find the diameter of the sun to the nearest kilometre if its distance from the earth is 149000000 km and it subtends an angle of 31 ' at the earth

plz help
thnkss

 

[tommykins]

Sorry for keeping the other topic off topic - but heres what you do.

It draws out a right angled triangle with 149 000 000 km as the hypotenuse. The diameter of the sun is the "x" (opposite side) and the 31' is the angle.

Convert 31' into radians.

Since sin x = Opposite/Hypotenuse, then sin 31' = x/149 000 000

thus x = 149 000 000 * sin 31'

 

[atakach99]

heyy man the answer in the back of the book is 1 343 622 km

is this the answer ur getting????

 

[tommykins]

Answers are wrong I think.

sin(0'31') * 149 000 000 = 1 345 594.426 km

 

[atakach99]

yea possibly

 

[lyounamu]

Sorry for keeping the other topic off topic - but heres what you do.

It draws out a right angled triangle with 149 000 000 km as the hypotenuse. The diameter of the sun is the "x" (opposite side) and the 31' is the angle.

Convert 31' into radians.

Since sin x = Opposite/Hypotenuse, then sin 31' = x/149 000 000

thus x = 149 000 000 * sin 31'

Isn't x the arc in your case (because you converted it to the radian)? I thought we were finding the diameter.

 

[tommykins]

Probbaly, figured that radian is not required, using normal 31' still however yeilds a different result. Pretty confident with it though.

 

[robbo2202]

i figure if u divide it into 2 otherwise u won't have a right angle.
hence,
sin 0 degrees 15.5' = x/149000000
x=671,804.0417
multiply this by 2 (coz so far u have only found the radius)
hence diameter = 1,343,608.083

 

[tommykins]

Oh yes, fogot about that step