Question 1071980
<pre><b><font size=4>
Use the law of cosines in this form:

{{{cos(ANGLE)}}}{{{""=""}}}{{{

matrix(1,16,"(SUM",OF,SQUARES,OF,THE,TWO,ADJACENT,"SIDES)","",""-"","","(SQUARE",OF,THE,OPPOSITE,"SIDE)") /

matrix(1,8,

TWICE,THE,PRODUCT,OF,THE,TWO,ADJACENT,SIDES)



}}}

The two shorter sides, 17 and 22, are the adjacent sides,
and the longest side, 27, is the opposite side.  So A is
the largest angle:

{{{cos(A)}}}{{{""=""}}}{{{ (17^2+22^2-27^2)/(2*17*22)}}}

{{{cos(A)}}}{{{""=""}}}{{{ (289+484-729)/748}}}

{{{cos(A)}}}{{{""=""}}}{{{ 44/748}}}

{{{cos(A)}}}{{{""=""}}}{{{ 1/17}}}

{{{A}}}{{{""=""}}}{{{"86.62771332°"}}}

Round off as you were told.

Edwin</pre></b></font>