Answer:
[tex]13x + 10x + 21 = 90 \\ 23x + 21 = 90 \\ 23x = 69 \\ x = 3[/tex]
The measure of angle DEH
[tex]13(3) = 39 \: degrees[/tex]
commercial angle FEH
[tex]10(3) + 21 = \\ 30 + 21 = 51 \: degrees[/tex]
