A surface of area `1 m^2` kept perpendicular to the sun rays absorbs 3 MJ of solar energy in one hour.
What is the amount of solar energy absorbed by a solar heater when a surface of area `9 m^2` is exposed perpendicular to the sun rays for 4 hours.

Explanation

To solve the problem, we need to determine the amount of solar energy absorbed by a solar heater with a surface area of 9 m² when exposed to sunlight for 4 hours, given that a surface area of 1 m² absorbs 3 MJ of solar energy in 1 hour.

### Step-by-Step Solution:

1. **Identify the energy absorbed per unit area per hour**:
- We know that 1 m² absorbs 3 MJ of solar energy in 1 hour.

2. **Calculate the energy absorbed by 9 m² in 1 hour**:
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