Which amongst the following statements is/are  not correct ?

1.      Isthmus is a narrow strip of land joining two landmasses.

2.      The North America continent liescompletely in the Northern and Western Hemisphere.

3.      World's longest mountain range and thelargest river are in the South America

Which of the statement(s) given above is/ are correct ?

The lengths of three medians in a triangles are 21 cm, 28 cm, 35 cm. What is the area of that traingle (in cm ² )?

Find the radius of the sphere whose volume is 562.5Ï€ cm³

ABCD is a square. P, Q, R and S are points on the sides AB, BC, CD and DA respectively such that AP = BQ = CR = DS. Angle  SPQ equal to ?

The area of the largest triangle inscribed in a semi-circle of radius R is-

A circular clock has the hour hand of length 42 cm. Find the length of the distance it covers by its tip from 11 p.m. to 3 a.m.

In the given figure. ABCDEF is a regular hexagon whose side is 6 cm. APF, QAB, DCR and DES are equilateral triangles. What is the area (in cm²

In ∆ABC , G is the centroid , AB = 5 cm, BC= 6 cm and AC = 7 cm , find GD, where D is the mid-point of BC?

ABC is an isosceles triangle inscribed in a circle. If AB = AC = 12√5 and BC = 24 cm then radius of circle is