What number should be placed in the box to help complete the division calculation? long division setup showing an incomplete calculation. 12 is in the divisor, 8587 is in the dividend, and 7 hundreds and 1 tens is written in the quotient. 8400 is subtracted from 8587 to give 187. An unknown value represented by a box is being subtracted from 187.

120

Step-by-step explanation:

Your description is a little different from below picture, but the logic is the same. The 1 in the tens position represents 10x12 = 120, hence 120 should be subtracted and leaves you with 67 to continue.

dc=6 square root of 3 and ac is 12 square root 3

c and d

step-by-step explanation:

square root of 3/2 = 18/c

cross multiply to get 18*2=√3*c

36/√3 * √3/√3 = c

c= 36*√3/3

c=12√3