Question

plz help me in solving 9th, 10th and 12th sums... ​

Answer 1

Answer:

Step-by-step explanation:

Question:-9

The figure formed by the given points will be a triangle.

Given points are:-

A(1,4) , B(-4,1) and C(4,1).

Let x1,x2 and x3 be 1, -4 and 4 resp.

and y1,y2 and y3 be 4, 1 and 1 resp.

Area of triangle=

=> 1/2[x1(y2-y3)+x2(y3- y1)+x3(y1-y2)]

=> 1/2[1 (1-1) + (-4)(1-4) + 4(4-1)]

=> 1/2[ 0 + 12+ 12]

=> 1/2 (24)

=> 12 sq. Units. Ans

Question:-10

On x-axis the y co-ordinate is 0.

So, on x-axis the coordinates is (x,0)

According to question:-

Points on x-axis is 4 units away from the origin.

So, the coordinates are (4,0). Ans.

Question:-12

Incorrect ∑xi = 25*78.4 = 1960

Correct ∑xi = Incorrect ∑xi - Incorrect value + Correct value

= 1960 - 69 + 96 = 1987

Correct mean = Correct ∑xi / n

= 1987 / 25

= 79.48

Therefore, correct mean is 79.48