Question

A parallelogram has side lengths of 4 and 6 and an angle of measure 55°. Law of cosines: a2 = b2 + c2 – 2bccos(A) What is x, the length of the diagonal, to the nearest whole number? 3 5 6 7

Answer 1

Sorry, but I just took the pre-test and the answer is actually 5

Answer 2

Answer: The correct answer is 5.

Solution:het

Given : In image attached

a =?, b = 6, c = 4 , A =
`55^o`

Law of cosines:
`a^2=b^2+c^2-2bccosA`

`a^2=(6)^2+(4)^2-2(6)(4)cos55^o=36+16-2(6)(4)0.5735`

(cos
`55^o`=0.5735)

`a^2=24.472,a=4.94\approx 5`

The length of the diagonal 'a' is 5.