The answer choices are:
a.125 cm squared
b.150 cm squared
c.100 cm squared
d.175 cm squared
i put b.150 but it was wrong. can someone me ?

10×15=150 5×5=25 150-25=125... A. 125

just have to find the area of the whole thing (10×15), then subtract the small square that isnt a part of it. because the lines on the right side are all equal, they are all 5cm. so, 5×5 is the area of that. subtract 25 from 150. that's your answer. hope it helps :)