the diagram shows a triangle.\nwhat is the value of ( b )?\n( b = square^circ )

Explanation:

Step1: Sum triangle angles to 180°

$2b + 2b + 40^\circ = 180^\circ$

Step2: Combine like terms

$4b + 40^\circ = 180^\circ$

Step3: Isolate term with $b$

$4b = 180^\circ - 40^\circ$ $4b = 140^\circ$

Step4: Solve for $b$

$b = \frac{140^\circ}{4}$

Answer:

$35^\circ$