WAEC - Mathematics (1997 - No. 23)
From the diagram above, which of the following is true?
a +b + x =180
a = b + x
a – b = 180 - x
a + b = x + 180
a – b = x - 180.
설명
From the diagram, the angles in the triangle are:
(180 - a)°, (180 - b)° and x°.
\(\therefore\) (180 - a) + (180 - b) + x = 180°
360 + x - a - b = 180°
360 - 180 + x = a + b
180 + x = a + b.