HELP ME, PLEASE. given: the tetrahedron ABCD
m∠BAC = 60°
m∠ CAD = 120°
E is the foot of the inner bisector of ∠A of ΔABD.
prove: ΔACE is a right triangle

1 In the diagram below, ABC ≅ DEF.

Which sequence of transformations maps ABC onto DEF?

2 On the set of axes below, the vertices of PQR have coordinates P(6,7), Q(2,1), and R(1,3).

What is the area of PQR?

3 In right triangle ABC, m∠C = 90°. If cos B = 5/13, which function also equals 5/13?

4 In the diagram below, mABC = 268°.

What is the number of degrees in the measure of ∠ABC?

5 Given MRO shown below, with trapezoid PTRO, MR = 9,MP = 2, and PO = 4.

What is the length of TR?

6 A line segment is dilated by a scale factor of 2 centered at a point not on the line segment. Which statement regarding the relationship between the given line segment and its image is true?

7 Which figure always has exactly four lines of reflection that map the figure onto itself?

8 In the diagram below of circle O, chord DF bisects chord BC at E.

If BC 12 and FE is 5 more than DE, then FE is

9 Kelly is completing a proof based on the figure below.

She was given that ∠A ≅ ∠EDF, and has already proven AB ≅ DE.

Which pair of corresponding parts and triangle congruence method would not prove ABC ≅ DEF?

10 In the diagram below, DE divides AB and AC proportionally, m∠C = 26°, m∠A = 82°, and DF bisects ∠BDE.

The measure of angle DFB is:

I. Diagonals are perpendicular bisectors of each other.

II. Diagonals bisect the angles from which they are drawn.

III. Diagonals form four congruent isosceles right triangles.

1 x=22.52

2: 65/39=604+39x

65x-39x=604

26x=604

x=604/26

×=23.23

see explanation

step-by-step explanation:

a

(6r + 7) + (13 + 7r) ( remove brackets and collect like terms )

= 6r + 7 + 13 + 7r

= 13r + 20

b

remove brackets and collect like terms

13 - r - 1 + r

= 12 - r

c

remove brackets and collect like terms

= - 8 - r + 2r - 4

= - 12 + r

d

remove brackets and collect like terms

= 7r - - - 6r

[-   - = - - = - ]

= r -