Step by step explanation: Triangle rule states that all angles of a trundle must equal to 180 degrees. So we have two known angles, therefore we can subtract them from the 180 degree total. 180-109-43 =28 Now to solve for x we have the equation 4x-16=28 We add 16 to both sides to isolate x 4x=44 Now we divide each side by 4 to get rid of the coefficient x=11
