Step-by-step explanation:
the area of a triangle is
baseline × height / 2
we have here 2 triangles : the larger, outer shaded one, and the smaller, inner white one.
to get the area of the shaded part, we need to calculate the area of the large triangle and subtract the area of the smaller triangle.
large area :
12 × 15 / 2 = 6 × 15 = 90 ft²
small area :
8 × 10 / 2 = 4 × 10 = 40 ft²
the shaded area is
90 - 40 = 50 ft²
What do you need help with?
(b)+(b+45)=215
b = # of boys
there are 45 more girls than boys and 215 students total.
minus 45 on both sides leaving you with
(b)+(b)=170
combine like terms leaving you with
2b=170
divide both sides by 2
b=85
there were 85 boys
85+45=130
(the 45 for the # of girls more than boys)
there were 130 girls.