Question

Work out the lengths of sides a and b.

Give your answers to 1 decimal place.
45 cm
20 cm
a
5 cm
b
3 cm

Answer 1

Side length A is 5.8cm

Side length B is 40.3cm

Explanation:

To find A:

5^2+3^2=34

square root of 34= 5.83...

round to 5.8

To find B:

45^2-20^2= 1625

square root of 1625= 40.3112...

round to 40.3

Answer 2

They are right triangles so you can use the Pythagorean theorem.

A = sqrt(5^2+3^2)

A = sqrt(25+9)

A = sqrt(34) (exact answer)

As a decimal it would be: 5.8

B = 45 = sqrt( 20^2 + b^2)

B^2 = 45^2-20^2

B^2 = 2025-400

B^2 = 1625

B = sqrt(1625)

B = 5sqrt(65) exact answer

As a decimal : 40.3