Thank you for the opportunity to help you with your question!
The sin of an angle is equalt to the length of the opposite side divided by the length of the hypotenuse. So inthis problems, for angle A, the opposite side is 10 and the hypotenuse is 26. For angle B the opposite side is 24 and the hypotenuse is 36.
Sin A = 10/26 = 5/13
Sin B = 24/26 = 12/13
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