After being found delinquent, R.E.H. was committed to a secured juvenile facility. A social worker at the facility petitioned for extension of the commitment within a year after it was made, and the court, after a hearing, extended the commitment for an additional year. R.E.H. contends that the extension order is void because the state failed to show at the time of the extension hearing that he was dangerous to himself or others. Because we conclude that the state need not show dangerousness in order to obtain an extension of commitment orders and that the court did not abuse its discretion in extending the commitment, we affirm.
R.E.H. was committed to the Lincoln Hills School after being found delinquent for operating a motor vehicle without the owner’s consent. While committed to Lincoln Hills pursuant to the finding of delinquency, R.E.H. was absent without leave on two occasions. Due to disciplinary incidents, he also spent a substantial portion of his time in a more restrictive environment. A social worker from Lincoln Hills filed a report with the petition for extension of the dispositional order, which contained allegations that R.E.H. was still uncontrollable and needed continuing assistance with his problems.
Section 48.865, Stats., provides for extension of juvenile dispositional orders.2 Any order of extension must *649comply with sec. 48.355, Stats.3 R.E.H. argues that be*650cause sec. 48.355(1) refers to sec. 48.34, Stats.,4 a deter*651mination of dangerousness must be made in order to extend a dispositional order under sec. 48.365. He argues that because a child cannot initially be placed in a secured *652facility unless he has been found to be a danger to the public, a dispositional order cannot be extended unless a further finding of dangerousness is made.
Because the legislature has specifically provided for extension of dispositional orders in sec. 48.365, no extension may be ordered except as set forth in that statute. An extension order can be entered only after compliance with sec. 48.365, which includes a requirement that the court comply with the provisions of sec. 48.355. Neither sec. 48.365 nor sec. 48.355 require a finding of dangerousness. The legislature requires such a finding only when the court initially places a juvenile in a secured setting. R.E.H. asks us to also apply that requirement to the extension of a dispositional order.
When the legislature enacts a statute, it is presumed to act with full knowledge of the existing laws and statutes.5 This is particularly true when the statutes under consideration are enacted as part of the same piece of legislation. While a determination of delinquency or dangerousness is required at the time of the original dispositional hearing, the legislature has expressed a different purpose in the extension provisions. If the placement has not met the objectives of the treatment, care or rehabilitation as specified in the original dispositional order, or the child’s adjustment has not reached the point where the court can terminate control or provide less restrictive control, the dispositional order may be extended.6 Since the child has already been adjudged delinquent or dangerous, a rehearing on these matters would be redundant. Rather, the purpose of the hearing to extend the dispositional order is to evaluate the child’s progress and to determine whether continued control is *653necessary. The decision to extend the order is within the discretion of the court and is to be based upon the evidence presented.7
Generally, before a court may review matters outside of the statutory language in order to determine an intended meaning, the statute must be unclear or ambiguous.8 Ambiguity exists in the statute only when reasonably well-informed persons can understand it in two or more different senses.9 We see no ambiguity or lack of clarity in sec. 48.365. It specifically delineates the parameters of the court’s authority in extending disposi-tional orders. Although it provides due process safeguards for the juvenile, it does not contain any requirement that the state prove the continued dangerousness of the juvenile.
In this instance, the court found that R.E.H. was not willing to abide by the rules of his home, school, or community and was in need of continued strict supervision. The court found that it was not only necessary, but also in R.E.H.’s best interest, to continue the commitment to Lincoln Hills. These findings support the court’s exercise of discretion in continuing the commitment of R.E.H. and are not against the great weight and clear preponderance of the evidence.
By the Court. — Order affirmed.