To answer this question you just need to divide the fabric she has( 7/8 yard of fabric) with the amount of fabric needed per shirt(2/7 yard of fabric). Then the calculation would be:
Number of shirt= fabric she has / fabric needed per shirt
Number of shirt = 7/8 yard / (2/7 yard/shirt)
Number of shirt = 7/8 yard * (7/2 shirt/yard)= 49/16 shirt= 3.065 shirts.
If you round it up, it should be 3 shirts.
(x + 2)/2 = (x - 6)/10
5(x + 2) = x - 6
5x + 10 = x - 6
5x - x = -6 - 10
4x = -16
x = -16/4 = -4
x = -4
If it’s a half circle, the central angle should be 180 degrees.