To find the number of giraffes weighing less than 700 kg, we first calculate the z-score for 700 kg using the formula:

\(z = \frac{X - \mu}{\sigma}\)

where \(X = 700\), \(\mu = 830\), and \(\sigma = 120\).

\(z = \frac{700 - 830}{120} = -1.083\)

Next, we find the probability that a giraffe weighs less than 700 kg, \(P(X < 700)\), which is equivalent to \(P(z < -1.083)\).

Using standard normal distribution tables or a calculator, \(P(z < -1.083) = 0.1394\).

Therefore, the expected number of giraffes weighing less than 700 kg is:

\(430 \times 0.1394 = 59.9\)

Rounding to the nearest whole number, we get 59 or 60 giraffes.