I think it’s 15 I hope it helps
Answer:
There is a little paper clip icon at the bottom of the answering or posting a question box that pulls up. Just click on it and it will give you the option to add an attachment.
Step-by-step explanation:
Explanation:
1. ∠BAC≅∠BCA, ∠ABD≅∠ADB; Reason: definition of isosceles triangles
2. ∠ABD +∠BAC +∠ADB = 180°; Reason: sum of internal angles is 180°
3. ∠BAC = 180° -2(∠ABD) = 36°; Reason: Subtraction and substitution properties of equality
4. ∠BAC +∠BCA +∠ABC = 180°; Reason: sum of internal angles is 180°
5. ∠BCA = 180° -2(∠BAC) = 108°; Reason: Subtraction and substitution properties of equality
6. ∠ABD +∠DBC = ∠ABC; Reason: Angle sum theorem
7. ∠DBC = ∠ABC -∠ABD = 108° -72° = 36°; Reason: Subtraction and substitution properties of equality
8. ∠BCA = ∠BAC = 36°; Reason: Substitution property of congruence
9. ΔBCD is isosceles; Reason: Base angles DBC and BCA are congruent.
_____
There may be extra steps involved if you separately use subtraction and substitution properties of equality, or if you separately claim congruence of angles and equality of their measures. We have assumed that the definition of "isosceles triangle" includes the fact of equal side lengths <u>and</u> equal base angles.
Answer:
Please mark be brainliest and I hoped this helped!
x = 45°
Step-by-step explanation:
Since this is an isosceles triangle, that means that x, and the angle opposite from x, are the same. We take 135° and subtract that from 180°. That gives us 45°. Since the angle opposing x is 45°, then x is 45° as well.