Help please i need so much help

6) in order  51º; 18º;123º;39º

7) in order   51º; 34º;95º;38º;47º;74º;59

Step-by-step explanation:

a triangle is 180º so 180-72-57=51

x+72=90        x=18

a line is 180º  so 180-57=x         x=123

a triangle is 180º  so 180-123-18=39

diagonals are congruent

180-129=51

180=51-95+x         x=34

180=47+95+x        x=38

180=59+x+47        x=74

300pi

step-by-step explanation:

x = ±sqrt(10)

step-by-step explanation:

5 - 2x² = -15

subtract 5 from each side

5-5 - 2x² = -15-5

-2x^2   = -20

divide by -2 on each side

-2x^2   /-2= -20/-2

x^2 =10

take the square root on each side

sqrt(x^2 )=±sqrt(10)

x = ±sqrt(10)

check:

5 - 2x² = -15

+sqrt(10)

5 - 2(sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15

-sqrt(10)

5 - 2(-sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15