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.