Quantitative Aptitude - Arithmetic Ability Questions

What is the area (in sq cm) of a rhombus if the lengths of the diagonals are 12 cm and 14 cm?

The line passing through (­3,4) and (0,3) is perpendicular to the line passing through (5,7) and (4,x). What is the value of x?

The length of one side of a rhombus is 13 cm and one of the diagonals is 10 cm. What is the legth of the other diagonal?

Find two numbers such that their mean proportion is 12 and third proportion is 768.

The surface area of a sphere is 1386 cm2.  Find its diameter (in cm)

Of the 3 numbers whose average is 40, the first is 1/3 rd the sum of other 2. What is the first number?

Among three numbers, the first is twice the second and thrice the third, If the average of three numbers is 517, then what is the difference between the first and the third number?

In ΔABC, AD is the median and AD = (1/2)BC. If ∠ACD = 40°, then what is the value (in degrees) of ∠DAB?