The answer to your problem is 11
This pic is the answer i believe

<u>Given</u><u> </u><u>2</u><u> </u><u>right</u><u> </u><u>angles</u><u>,</u><u> </u><u>are</u><u> </u><u>always</u><u> </u><u>supplementary</u><u> </u><u>and</u><u> </u><u>congruent</u>