To verify whether the diagonals are perpendicular to each other, we find the slope of each segment and we can see that the slopes should be opposite reciprocals of each other.This means, these segments are really perpendicular. This theorem can be verified through congruent angles present in the quadrilateral.
Answer:
r = - 2.5

Step-by-step explanation:
21r - 7 - r + 5 = - 52
20r - 2 = - 52
20r - 2 + 2 = - 52 + 2
20r = - 50
20r ÷ 20 = - 50 ÷ 20
r = - 2.5
Answer:
40 girls
Step By Step Explanation:
assume boys = y girls = x
y = 1/2x + 10
y = 30
30 = 1/2x + 10
1/2x = 20
x = 20 *2 = 40
girls is 40 boys is 30
12 x 8 = 96
96/2 = 48
it's an area equation so 48 m^2