Answer:
b1 = 3
Step-by-step explanation:
Substitute the known measure into the area formula:
60 = [tex]\frac{1}{2}[/tex](8)(b1 + 12)
60 = 4(b1 + 12)
/4 /4
15 = b1 + 12
-12 -12
3 = b1
b1 = 3
Now substitute b1 for 3 in the formula
60 = [tex]\frac{1}{2}[/tex](8)(3 + 12)
60 = 4(15)
60 = 60, which is correct
So the answer is b1 = 3
Hope this helps :)
