Please refer to the attached image.
-2/5, 4/5 and -2/5 + 4/5 have been marked in red in the image
The points marked on the number line are separated by a distance of 1/5.
So when you add 4/5 to -2/5 you need to move 1/5 4 times (4/5 = 4 x 1/5) towards the right to reach the SUM.
Based on this, the sum of -2/5 and 4/5 is 2/5, and has been highlighted in the image.
Answer:
31.7 cm²
Step-by-step explanation:
The area (A) of the triangle is calculated as
A = absinC
where a, b are the 2 sides given and C the angle between them
∠ C = 180° - (72 + 59)° = 180° - 131° = 49° , thus
A = 0.5 × 12 × 7 × sin49° ≈ 31.7 cm² ( to 1 dec. place )