Question

△mno and △pnr are shown below.
which statement is true?
△mno is similar to △pnr.
△mno is not similar to △pnr.
there is not enough information to determine whether the triangles are similar.

Explanation:

Step1: Find ∠MON in △MNO

In right △MNO, sum of angles is 180°.
$\angle MON = 180^\circ - 90^\circ - 31^\circ = 59^\circ$

Step2: Find ∠MPR in △PNR

In right △PNR, sum of angles is 180°.
$\angle MPR = 180^\circ - 90^\circ - 69^\circ = 21^\circ$

Step3: Compare triangle angle sets

△MNO angles: $31^\circ, 90^\circ, 59^\circ$
△PNR angles: $21^\circ, 90^\circ, 69^\circ$
No matching 3-angle pairs for similarity.

Answer:

△MNO is not similar to △PNR.