Subtract the sum of 126 and (-747) from the sum of 135 and (-136)

620

Step-by-step explanation:

the sum of 126 and(-747) = 126+(-747)

                                         = 126 -747       [positive plus negative=negative]

                                         =-621

the sum of 135 and (-136) =135+ (-136)= 135 -136

                                                             =-1

subtract ⇒

-1-(-621)  = -1+621           [negative plus negative=positive ]

               =620

the one on the bottom left

step-by-step explanation:

all of the other ones have a specific pattern

according to the triangle sum theorem, all the angles in a triangle must add up to 180 degrees. if we know one angle is already 90, we do 180-90=90. the other 2 angles must add up to 90, exactly.

step-by-step explanation: