Question

Find the 10th term of AP: 2.7.12....


DE//BC. Find AD.

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Answer 1

Answers:

1. Find the 10th term of an A. P 2 , 7 , 12

Answer:

a = 2

d = a2 - a1

d = 7 - 2

d = 5

a10 = a + 9d

a10 = 2 + 9(5)

a10 = 2 + 45

a10 = 47

2. DE || BC , AD = ?

Answer:

Given,

BD = 7.2 cm

AE = 1.8 cm

EC = 5.4 cm

By BPT,

$\frac{AD}{DB} = \frac{AE}{EC} \\ \\ \frac{AD}{7.2} = \frac{1.8}{5.4} \\ \\ AD = \frac{1.8 \times 7.2}{5.4} \\ \\ AD = \frac{12.96}{5.4} \\ \\ AD = 2.4 cm$