M1*v1=m2*v2
solve for m2 when m1=1.50,v1=4.2,andv2=5.0

M1*V1=M2*V2 
M2 = M1*V1 / V2
M2 = (1.50)(4.2) / 5.0
M2 = 6.3 / 5
M2 = 1.26

Answer: d. 39 cmin the diagram, the approximate length of the minor arc de is 39 centimetres.step-by-step explanation: the formula for the length of an arc in a circle is as displayed below.let the length of the minor arc de = xx = 2( pi )r × angle of sector / 360°from this, we will substitute the values given from the problem into the formula to obtain the length of the minor arc de.x = 2( pi )r × angle of sector / 360°r = radius = 25cmpi as an approximate value = 3.14angle of sector = 120°x = 2( 3.14 )( 25 ) × 120° / 360°x = 157 × 1 / 4x = 39.25x = 39 ( rounded to the nearest whole number as an approximate value )