Let a =70° and b= 10° (and a-b=70-10 =60)
We have the following trigonometric identity:
sin(a-b) = sin(a).cos(b)-sin(b).cos(a) OR:
sin(70-10) = sin70.cos10 - sin10.cos70
But sin(70-10) = sin(60) and we know that sin(60°) =(√3)/2
Answer:
142 sq cm
Step-by-step explanation:
You find the areas of each face, using area of a rectangle (length * width), to get: 7*3+7*3+7*5+7*5+3*5+3*5=21+21+35+35+15+15=<u>142</u>
and surely you know how much that is.
