Question

t1=4 , t3=4/9. find t7 and tn of this geometric sequence?​

Answer 1

Answer:

80

Step-by-step explanation:

1.  In quadrilateral ACBD, AC = AD and AB bisects ∠A )see figure). Show that ΔABC ≌ ΔABD. What can you say about BC and BD?



Ans. In quadrilateral ABCD we have

                  AC = AD

            and AB being the bisector of ∠A.

            Now, in ΔABC and ΔABD,

                  AC = AD

[Given]

                  AB = AB

[Common]

∠CAB = ∠DAB [∴ AB bisects ∠CAD]

            ∴ Using SAS criteria, we have

                  ΔABC ≌ ΔABD.

            ∴ Corresponding parts of congruent triangles (c.p.c.t) are equal.

            ∴ BC = BD.

2.  ABCD is a quadrilateral in which AD = BC and ∠DAB = ∠CBA (see Figure). Prove that

      (i) ΔABD ≌ ΔBAC

      (ii) BD = AC

      (iii) ∠ABD = ∠BAC.