Explanation:

Let’s break it down:

- The curved surface area (CSA) of a right circular cylinder is given by:

CSA = 2prh

You said CSA = 70p and height h = 7 cm.

- So, plugging in the numbers:

2pr × 7 = 70p

14pr = 70p

r = 70p / 14p = 5

- So, radius is 5 cm.

- Now, total surface area (TSA) = CSA + 2(Base area)

TSA = 2prh + 2pr²

TSA = 70p + 2p × (5)²

TSA = 70p + 2p × 25

TSA = 70p + 50p

TSA = 120p cm²

- Let’s check your options:

- 1: 140p cm²

- 2: 150p cm²

- 3: 180p cm²

- 4: 120p cm²

The correct answer is option 4: 120p cm².