CBSE Guess > Papers > Question Papers > Class X > 2009 > Mathematics > Mathematics
Q. 28 . Prove that the ratio of the areas of two similar triangles is equal to the square of the ratio of their corresponding sides. Using the above, do the following .
If D is a point on the side AC of 
such that
AD : DC = 2 : 3, and E is a point on BC such that
DE || AB; then find the ratio of areas of 
and 
.
Sol. Part I: See Theorem 2,
Page (xxxi).
Part II:
Let AD = 2k, CD = 3k
Then AC = 2k + 3k = 5k
Q. 29. The lengths of 40 leaves of a plant are measured correct up to the nearest millimetre and the data is as under . 6
| Length (in mm) | Number of leaves |
| 118 – 126 | 4 |
| 126 – 134 | 5 |
| 134 – 142 | 10 |
| 142 – 150 | 12 |
| 150 – 158 | 4 |
| 158 – 166 | 5 |
Find the mean and median length of the leaves.
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CBSE 2009 Question Papers Class X