Me !

what is the missing reason in steps 7 and 8 of the proof?

a. definition of sine in right triangle
b. definition of equilateral triangle

  A. definition of sine in right triangle

Step-by-step explanation:

Steps 6 to 10 are a copy of steps 2 to 5, using different vertices and sides. Since the two developments are substantially identical, the reasons will be identical:

  reason 7 = reason 8 = reason 2 = reason 3 = "definition of sine in right triangle"

(sin 42)/31. = sinx)/37

sinx = 37 (sin42)/31

= 37× 0.66/31 = 0.787

x= 51.9

other angle opposite to y = 180-51.9-42

= 180- 93.9 =86.1

so

sin42)/31 = sin 86.1)/y

0.021 = 0.997 /y

y= 0.997/0.021 =47.47