If a > 0 and b < 0, then which of the following must be true.
ab > 0
a + b < 0
a - b > 0
a + b > 0
b - a > 0

We need to find the correct answer on the given choices:

If a > 0 and b < 0, then The answer is a + b > 0
let’s give a specific example:
let’s have a = 1
and b = .20

Now, let’s try calculating if our answer is correct.
Thus a + b > 0
=> a + b
=> 1 + .20
=> 1.20
and 1.20 is greater than 0.
=>Therefore 1.20 > 0 = a + b > 0

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 )