The answer is D or the fourth choice, 12
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:
List price (original price) = $350
Discount amount ($ saved) = $133
Step-by-step explanation:
The list price is the sale price ($217) divided by the difference of 1 minus the result of the discount (38%) divided by 100.
Answer:
0
Step-by-step explanation:
pretty easy tbh
Step-by-step explanation:
Distribute:
=2x+(y)(5x)+(y)(−y)+(y)(3)
=2x+5xy+−y2+3y
Answer:
=5xy−y2+2x+3y
