Practice30 Create account

Two sides of a triangle are 18 cm and 10 cm, and its perimeter is 42 cm. Find its exact area in $cm^{2}$ .

Competition practiceAreas & Volumes

A21√11
B11√21
C42√11
D21√22

Step-by-Step Solution

Third side =

42 - (18 + 10) = 14

cm, and

s = 21

. Area = √

(21 \times 3 \times 11 \times 7)

= √4851. Since

4851 = 441 \times 11

, the area = 21√

11 cm^{2}

.

Answer: A) 21√11

Master this topic in 30 minutes a day.

Don't just memorise the answer — build a daily practice habit.

Practice 5 Similar Questions Free →

All Areas & Volumes practice questions

More Areas & Volumes practice

A parallelogram has adjacent sides 60 m and 25 m, and one of its diagonals is 65 m. Find…The diagonals of a rhombus measure 24 cm and 10 cm. Find its perimeter in cm.In a trapezium the parallel sides are 25 cm and 13 cm, and each of the two non-parallel…A rectangle measures 60 m by 20 m. A square has the same perimeter as this rectangle. By…A rectangular plot measures 40 m by 30 m. A path 2.5 m wide is laid all around it on the…